# Connecting Unified CM to Amazon Connect

Systems: Cisco Unified CM to Amazon Connect

For voice engineers connecting Cisco Unified Communications Manager to an Amazon Connect contact center.

Canonical: https://warmtransfer.net/guides/cucm-with-amazon-connect

Last verified: 2026-09-25

An Amazon Connect instance needs a claimed DID or toll-free phone number to place or receive calls[^28]. By default an Amazon Connect account can claim and release up to 200% of its phone-number quota in a rolling 180-day period[^6].

## Before you start

Exceeding the 200% threshold blocks further claims until an AWS support case is opened or the period expires[^6]. Amazon Connect requires phone numbers in E.164 format, for example +18005551212 for a US number[^18].

## What changes by situation

- How will customers' calls reach Amazon Connect? Port published contact-center numbers to Amazon Connect; Claim new Amazon Connect numbers and publish them; Forward published numbers from Unified CM over the PSTN.
- How will Amazon Connect hand calls back to Unified CM? Transfer over the PSTN to a Unified CM DID; Transfer over an external voice transfer connector.
- Where will agents answer Amazon Connect calls? Amazon Connect CCP softphone in the browser; Existing Unified CM desk phone.

## Step 1: Format destination numbers in E.164 and verify outbound country allowances

### Do
List every Unified CM DID that Amazon Connect will dial for transfers or desk-phone agent routing in E.164 format, such as +18005551212[^18]. A transfer to a phone number fails unless the instance is allowed to call the destination country; countries are added through a service quota increase request[^52].

### Verify
Place a test call to a listed number using the Contact Control Panel (CCP)[^3]. The CCP shows an Invalid number error when a dialled number is not in E.164 format or the destination country is not allowed for outbound calling on the instance[^3].

### Rollback
Suggested rollback: Update the internal records with the corrected E.164 numbers or adjust internal routing targets.

## Step 2: Claim an Amazon Connect working number

### Do
In the Amazon Connect admin website, numbers are claimed from Channels, Phone numbers, Claim a number, choosing a toll-free or DID number[^54]. WarmTransfer's reading of the sources is that only numbers claimed or ported to Amazon Connect can be the outbound caller ID number unless AWS Support activates an external number for custom caller ID after proof of ownership[^2].

### Verify
Confirm that the claimed phone number appears under Channels > Phone numbers[^29].

### Rollback
Release the claimed phone number, noting that an Amazon Connect phone number cannot be claimed again after it is released[^39][^55].

## Step 3: Publish the inbound contact flow and bind the number

### Do
A claimed or ported Amazon Connect number is attached to a flow on Channels > Phone numbers > Edit Phone number by choosing the flow under Flow / IVR, and only published flows appear in that list[^29].

### Verify
Call the claimed number from an external telephone and verify that the assigned flow executes[^29].

### Rollback
Edit the phone number on Channels > Phone numbers > Edit Phone number and select a different published flow under Flow / IVR[^29].

## Step 4: Direct inbound customer calls to Amazon Connect

**Port published contact-center numbers to Amazon Connect**

### Do
Submit a porting request in advance, because number porting must be requested in advance and its duration varies by country and complexity[^56]. Porting US or Canadian numbers to Amazon Connect typically takes 2 to 4 weeks after portability is verified and all documents are submitted correctly[^35]. Porting numbers from outside the US and Canada to Amazon Connect takes 2 to 6 months to complete[^33]. A port request for US DID or toll-free numbers cannot be submitted more than 30 days before the porting date[^34]. In most cases the losing carrier, not the customer, picks the date and time of a port to Amazon Connect[^32]. Do not cancel the existing telecom service until the numbers are ported and confirmed working in Amazon Connect; cancelling first can lose the number[^26].

### Verify
After the port, attach each ported number to the flow on Channels > Phone numbers > Edit Phone number under Flow / IVR, then call it from an outside phone[^29].

### Rollback
Do not cancel the existing telecom service until the numbers are ported and confirmed working in Amazon Connect[^26].

**Claim new Amazon Connect numbers and publish them**

### Do
Claim production DID or toll-free numbers from Channels, Phone numbers, Claim a number[^28][^54]. Attach each newly claimed number to the published flow in the Flow / IVR field before saving[^29][^54].

### Verify
Dial each claimed production number from an external phone and confirm that the flow answers[^29].

### Rollback
Release unneeded numbers, noting that an Amazon Connect phone number cannot be claimed again after it is released[^39][^55].

**Forward published numbers from Unified CM over the PSTN**

### Do
In Unified CM, configure routing following the call routing task flow, which runs translation patterns and transformation patterns, then optional route groups, route lists and route filters, then route patterns[^11]. Unified CM called party transformation patterns turn the global form of a called number into the local form an off-cluster gateway or trunk requires[^8]. In Unified CM a route list is a prioritised list of paths for a call, and a route group distributes the call to gateways and trunks[^9]. Configure a route pattern matching each published contact-center number to send matching calls to the gateway or route list, directing calls to the Amazon Connect DID[^10].

### Verify
Dial a published contact-center number from an external phone and confirm that the Amazon Connect flow answers[^29].

### Rollback
In Unified CM, delete or redirect the configured route pattern away from the Amazon Connect destination[^10].

## Step 5: Establish Unified CM dialing to Amazon Connect

### Do
In Unified CM, configure a route pattern matching an internal dial string and assign it to a route list and route group that egress to gateways and trunks over the PSTN[^10][^9]. In the field, community sources disagree on native SIP support, with one saying external voice transfer provides native SIP transfers out of Amazon Connect, and a later one saying inbound SIP trunking from on-premises systems into Amazon Connect is not publicly supported[^41].

### Verify
Dial the internal route string from a Unified CM phone and confirm that the Amazon Connect flow answers[^29].

### Rollback
Delete the route pattern in Unified CM[^10].

## Step 6: Configure outbound caller ID on queues

### Do
Set an outbound caller ID number on every queue, because Amazon Connect does not allow anonymous calls, so every queue, including the inbound queue used for agent-initiated external transfers, needs a valid outbound caller ID number or the call fails[^27]. Only numbers claimed or ported to Amazon Connect can be the outbound caller ID number unless AWS Support activates an external number for custom caller ID after proof of ownership[^2].

### Verify
The CCP shows Invalid outbound configuration when outbound calling is not enabled on the instance or the queue has no outbound caller ID; agents also need the CCP - Make outbound calls permission[^4].

### Rollback
Change the queue's outbound caller ID number[^27].

## Step 7: Configure agent audio endpoints

**Amazon Connect CCP softphone in the browser**

### Do
The CCP softphone needs outbound UDP 3478 to the Region's TurnNlb endpoints; without it agents see Failed to establish softphone connection and miss calls[^44]. AWS recommends the domain allowlist (Option 1) for CCP connectivity and testing it with more than 200 calls[^43]. Persistent connection is set per agent under Phone > Softphone in user management, works only in Chrome and Edge (not Firefox), and agents cannot turn it off themselves[^30].

### Verify
Run more than 200 test calls, noting that an error rate above 2 percent suggests a proxy problem and a move to the IP-range allowlist (Option 2)[^43]. Confirm that agents do not encounter Failed to establish softphone connection errors[^44].

### Rollback
Remove the allowlist entries and turn off persistent connection for the agent under Phone > Softphone[^30].

**Existing Unified CM desk phone**

### Do
In user management, configure the agent's phone to their Unified CM DID in E.164 form[^18]. When an agent's audio is rerouted to an existing device, Amazon Connect places an outbound call to that device for every call meant for the agent, and a missed answer puts the agent in a missed contact state[^17]. A call sent to an agent's desk phone counts as an outbound call from Amazon Connect and costs extra[^16]. A transfer to a phone number fails unless the instance is allowed to call the destination country[^52].

### Verify
Route a test contact to the agent, noting that an unanswered call leaves the agent in a missed contact state[^17].

### Rollback
Switch the agent back to softphone, which needs outbound UDP 3478 to the Region's TurnNlb endpoints[^44].

## Step 8: Configure call handoffs to Unified CM

**Transfer over the PSTN to a Unified CM DID**

### Do
For automated handoffs, add a Transfer to phone number block configured with the destination Unified CM DID in E.164 format[^18]. The Amazon Connect Transfer to phone number flow block handles voice only, takes chat, task and email contacts down its Error branch, and has Success, Call Failed, Timeout and Error branches[^50]. The block can be used in Inbound, Customer Queue, Transfer to Agent and Transfer to Queue flows[^49]. For a transfer made while the agent is on a call, caller ID comes from the inbound queue that handled the call and the outbound whisper flow cannot override it; to control it, use a Transfer to phone number block with an explicit caller ID[^47]. To set up phone number transfers for agents, create a phone number quick connect (it needs no flow), add it to a queue used for incoming contacts, and make sure that queue is in the transferring agents' routing profile[^48]. A phone number quick connect's number is entered starting with the country code, and outbound calls also need an outbound caller ID number set on the queue[^37]. A phone number quick connect invokes no flow, so its outbound caller ID cannot be set per transfer and comes from the queue configuration[^31]. Agents see only the quick connects attached to the queues in their routing profile including the default outbound queue, so a quick connect must be added to a queue on the Edit queue page[^38]. AWS advises against transferring calls to destinations that could transfer them back into Amazon Connect (circular transfers), because PSTN latency compounds[^1].

### Verify
In the CCP an agent transfers to an external number by calling it from Quick connects or the number pad, choosing Join once it connects, then choosing Leave to complete the transfer[^5]. Test the flow block across its Success, Call Failed, Timeout and Error branches[^50].

### Rollback
Remove the quick connect from the queue on the Edit queue page[^38]. Re-point the contact flow branch that used the Transfer to phone number block[^50].

**Transfer over an external voice transfer connector**

### Do
An Amazon Connect external voice connector is billed at $100 per connector per day (US West (Oregon) rate)[^20]. CUBE is a back-to-back user agent that terminates and originates SIP signaling and RTP/RTCP media and connects enterprise VoIP networks to ITSPs[^57]. CUBE provides address and port translation for topology hiding, DTMF, fax, modem and codec transcoding interworking, and delayed-offer to early-offer conversion[^58]. In Unified CM, the SIP trunk task flow is: configure SIP profiles, then the SIP trunk security profile, then the SIP trunk[^12]. An encrypted Unified CM SIP trunk uses a SIP trunk security profile with Device Security Mode set to Encrypted and TLS as the incoming and outgoing transport; the default TLS incoming port is 5061[^15]. Encrypted media over a Unified CM SIP trunk requires the SRTP Allowed check box on the trunk[^13]. A Unified CM SIP trunk accepts up to 16 destination addresses (IPv4, IPv6 or FQDN) or a single DNS SRV record[^14].

### Verify
Suggested check: Place a test transfer through the connector and verify that the destination extension rings. Confirm that the $100 per connector per day charge appears in billing[^20].

### Rollback
Revert the flow to a Transfer to phone number block, which handles voice only[^50]. Delete the connector to stop the $100 per connector per day billing[^20].

## Step 9: Configure context and metadata propagation

**Transfer over the PSTN to a Unified CM DID**

### Do
When the Transfer to phone number block has no custom caller ID, the external party sees the customer's own caller ID[^51]. To control it, use a Transfer to phone number block with an explicit caller ID[^47].

### Verify
Transfer a test call from the block and verify the calling party number displayed on the destination device[^51].

### Rollback
Suggested rollback: Adjust or clear the custom caller ID parameter in the transfer block to restore default calling party presentation.

**Transfer over an external voice transfer connector**

### Do
In Unified CM, configure the SIP trunk pointing to CUBE using task-flow order[^12].

### Verify
Suggested check: Inspect a SIP INVITE captured at the demarcation boundary to verify message headers.

### Rollback
Suggested rollback: Remove any custom routing elements or profile adjustments applied to the trunk.

## Step 10: Perform end-to-end testing and review call anchoring

### Do
Run test calls across the configured paths: outside callers into Amazon Connect, internal calls to Amazon Connect, and transfers to Unified CM endpoints[^25]. An external transfer from Amazon Connect stays anchored to the instance's Region for the whole call: per-minute usage accrues until the transfer recipient hangs up, and the call is not recorded after the agent drops or the transfer completes[^25]. The block's Resume flow after disconnect option returns the caller to the Amazon Connect flow only when the external party hangs up; if the customer hangs up, the whole call ends[^53].

### Verify
Verify that external transfers create contact records that stay anchored to the Region for the whole call[^25].

## See also

- [Amazon Connect with Salesforce Service Cloud Voice](https://warmtransfer.net/knowledge/amazon-connect-with-salesforce-voice)
- [Microsoft Teams with Amazon Connect](https://warmtransfer.net/knowledge/teams-with-amazon-connect)
- [Connecting Unified CM to Five9](https://warmtransfer.net/knowledge/cucm-with-five9)

## Applicability

Applies to: Amazon Web Services Amazon Connect, Cisco Unified Communications Manager, Salesforce Voice, and Cisco Unified Border Element. Deployments: on-premises and multi-tenant. Sources checked 2026-09-25. External voice connector daily pricing of $100 per connector per day is specific to region us-west-2[^20].

## What remains uncertain

Sources disagree on external voice per-minute pricing, as the current pricing appendix lists external voice minutes at $0.012 per minute, or $0.032 per minute when Amazon Connect unlimited AI is enabled[^23]. The complete list of AWS Regions supporting external voice transfer connectors is not covered by the sources below. The specific desk-phone per-minute rate from Amazon Connect to off-cluster Unified CM destinations is not covered by the sources below. Whether customer caller ID is retained across carrier-level call forwarding from Unified CM to Amazon Connect is not covered by the sources below. External voice transfer connector configuration fields, destination parameter syntax, User-to-User Information (UUI) encoding, and SBC TLS cipher suite requirements are not covered by the sources below. Direct native SIP trunking to deliver new calls from on-premises PBXs into Amazon Connect is not covered by the sources below. Inbound call routing from Unified CM into Amazon Connect using CUBE transcoding to Opus is not covered by the sources below. Screen pop, CTI integration, and phone recording synchronization when using Unified CM phones as agent desk phones are not covered by the sources below. The procedure to port phone numbers away from Amazon Connect back to Unified CM or another carrier is not covered by the sources below.

## Sources

[^1]: AWS advises against transferring calls to destinations that could transfer them back into Amazon Connect (circular transfers), because PSTN latency compounds. Source: [Set up your network to use the Connect Customer Contact Control Panel (CCP)](https://docs.aws.amazon.com/connect/latest/adminguide/ccp-networking.html), Region selection considerations > External transfers (last sentence). Checked 2026-09-25.
[^2]: Only numbers claimed or ported to Amazon Connect can be the outbound caller ID number unless AWS Support activates an external number for custom caller ID after proof of ownership. Source: [Set up outbound caller ID in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/queues-callerid.html), Outbound parameters: Set in queue > Outbound caller ID number. Checked 2026-09-25.
[^3]: The CCP shows an Invalid number error when a dialled number is not in E.164 format or the destination country is not allowed for outbound calling on the instance. Source: [Contact Control Panel (CCP) Issues](https://docs.aws.amazon.com/connect/latest/adminguide/common-ccp-issues.html), CCP invalid number issues. Checked 2026-09-25.
[^4]: The CCP shows Invalid outbound configuration when outbound calling is not enabled on the instance or the queue has no outbound caller ID; agents also need the CCP - Make outbound calls permission. Source: [Contact Control Panel (CCP) Issues](https://docs.aws.amazon.com/connect/latest/adminguide/common-ccp-issues.html), CCP outbound configuration issues > How to fix. Checked 2026-09-25.
[^5]: In the CCP an agent transfers to an external number by calling it from Quick connects or the number pad, choosing Join once it connects, then choosing Leave to complete the transfer. Source: [Transfer calls to a quick connect or external phone number using the Contact Control Panel (CCP)](https://docs.aws.amazon.com/connect/latest/adminguide/transfers.html), To transfer to a quick connect or to an external number, steps 1-4. Checked 2026-09-25.
[^6]: By default an Amazon Connect account can claim and release up to 200% of its phone-number quota in a rolling 180-day period; exceeding that blocks further claims until an AWS support case is opened or the period expires. Source: [Get a local toll-free or DID Connect Customer phone number](https://docs.aws.amazon.com/connect/latest/adminguide/claim-phone-number.html), Avoid being blocked from claiming or releasing too many numbers. Checked 2026-09-25.
[^7]: An independent integration guide places Cisco Unified Border Element between Unified CM and the Amazon Connect external voice transfer connector, with CUBE trunking to the connector (inferred). Source: [A Technical Guide to Amazon Connect & Cisco CUCM Integration](https://intelligentvisibility.com/guide-amazon-connect-cisco-cucm-integration), External Voice Transfer Connector; Cisco CUBE Role. Checked 2026-09-25.
[^8]: Unified CM called party transformation patterns turn the global form of a called number into the local form an off-cluster gateway or trunk requires. Source: [System Configuration Guide for Cisco Unified Communications Manager Release 15 and SUs - Configure Call Routing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_010010.html), Configure Call Routing > Called party transformation patterns. Checked 2026-09-25.
[^9]: In Unified CM a route list is a prioritised list of paths for a call, and a route group distributes the call to gateways and trunks. Source: [System Configuration Guide for Cisco Unified Communications Manager Release 15 and SUs - Configure Call Routing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_010010.html), Configure Call Routing > Route groups and route lists overview. Checked 2026-09-25.
[^10]: Unified CM matches an external dial string against configured route patterns and sends the call to the gateway or route list that the matching pattern names. Source: [System Configuration Guide for Cisco Unified Communications Manager Release 15 and SUs - Configure Call Routing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_010010.html), Configure Call Routing > Route patterns overview; Configure Route Patterns procedure. Checked 2026-09-25.
[^11]: The Unified CM call routing task flow runs translation patterns and transformation patterns, then optional route groups, route lists and route filters, then route patterns. Source: [System Configuration Guide for Cisco Unified Communications Manager Release 15 and SUs - Configure Call Routing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_010010.html), Call Routing Configuration Task Flow. Checked 2026-09-25.
[^12]: The Unified CM SIP trunk task flow is: configure SIP profiles, then the SIP trunk security profile, then the SIP trunk. Source: [System Configuration Guide for Cisco Unified Communications Manager Release 15 and SUs - Configure Trunks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_01000.html), Configure Trunks > SIP Trunk Configuration Task Flow. Checked 2026-09-25.
[^13]: Encrypted media over a Unified CM SIP trunk requires the SRTP Allowed check box on the trunk. Source: [System Configuration Guide for Cisco Unified Communications Manager Release 15 and SUs - Configure Trunks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_01000.html), Configure Trunks > Configure SIP Trunks. Checked 2026-09-25.
[^14]: A Unified CM SIP trunk accepts up to 16 destination addresses (IPv4, IPv6 or FQDN) or a single DNS SRV record. Source: [System Configuration Guide for Cisco Unified Communications Manager Release 15 and SUs - Configure Trunks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_01000.html), Configure Trunks > Configure SIP Trunks. Checked 2026-09-25.
[^15]: An encrypted Unified CM SIP trunk uses a SIP trunk security profile with Device Security Mode set to Encrypted and TLS as the incoming and outgoing transport; the default TLS incoming port is 5061. Source: [System Configuration Guide for Cisco Unified Communications Manager Release 15 and SUs - Configure Trunks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_01000.html), Configure Trunks > Configure SIP Trunk Security Profile. Checked 2026-09-25.
[^16]: A call sent to an agent's desk phone counts as an outbound call from Amazon Connect and costs extra. Source: [Manage agent desk phone settings with a custom Contact Control Panel](https://aws.amazon.com/blogs/contact-center/manage-agent-desk-phone-settings-with-a-custom-contact-control-panel), Introduction (second paragraph). Checked 2026-09-25.
[^17]: When an agent's audio is rerouted to an existing device, Amazon Connect places an outbound call to that device for every call meant for the agent, and a missed answer puts the agent in a missed contact state. Source: [Set up your network to use the Connect Customer Contact Control Panel (CCP)](https://docs.aws.amazon.com/connect/latest/adminguide/ccp-networking.html), Rerouting audio. Checked 2026-09-25.
[^18]: Amazon Connect requires phone numbers in E.164 format, for example +18005551212 for a US number. Source: [Set up outbound caller ID in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/queues-callerid.html), Use E.164 format for international phone numbers. Checked 2026-09-25.
[^19]: From May 1, 2025, an external voice transfer connector was priced at $3,100 per month. Source: [Amazon Connect external voice pricing changes](https://aws-news.com/article/0196b1c4-2515-5760-3ad9-74e62ba826b0), External Voice Transfer Pricing, first bullet. Checked 2026-09-25.
[^20]: An Amazon Connect external voice connector is billed at $100 per connector per day (US West (Oregon) rate). Source: [Amazon Connect Customer Pricing Appendix](https://aws.amazon.com/products/connect/customer/pricing/appendix/), External voice > External voice connector. Checked 2026-09-25.
[^21]: At launch in December 2024, Amazon Connect external voice transfer was available only in US East (N. Virginia) and US West (Oregon). Source: [Amazon Connect now supports external voice transfers](https://aws-news.com/article/2024-12-02-amazon-connect-now-supports-external-voice-transfers), announcement, availability sentence. Checked 2026-09-25.
[^22]: The May 2025 pricing change set external voice transfers at $0.005 per minute (disputed). Source: [Amazon Connect external voice pricing changes](https://aws-news.com/article/0196b1c4-2515-5760-3ad9-74e62ba826b0), External Voice Transfer Pricing, second bullet. Checked 2026-09-25.
[^23]: The current pricing appendix lists external voice minutes at $0.012 per minute, or $0.032 per minute when Amazon Connect unlimited AI is enabled (disputed). Source: [Amazon Connect Customer Pricing Appendix](https://aws.amazon.com/products/connect/customer/pricing/appendix/), External voice > External voice minutes. Checked 2026-09-25.
[^24]: Amazon Connect external voice transfer moves voice calls and their metadata between Amazon Connect and another voice system without using the public telephone network. Source: [Amazon Connect now supports external voice transfers](https://aws-news.com/article/2024-12-02-amazon-connect-now-supports-external-voice-transfers), announcement, first paragraph. Checked 2026-09-25.
[^25]: An external transfer from Amazon Connect stays anchored to the instance's Region for the whole call: per-minute usage accrues until the transfer recipient hangs up, and the call is not recorded after the agent drops or the transfer completes. Source: [Set up your network to use the Connect Customer Contact Control Panel (CCP)](https://docs.aws.amazon.com/connect/latest/adminguide/ccp-networking.html), Region selection considerations > External transfers. Checked 2026-09-25.
[^26]: Do not cancel the existing telecom service until the numbers are ported and confirmed working in Amazon Connect; cancelling first can lose the number. Source: [When do I cancel my current telecom service when porting numbers to Connect Customer?](https://docs.aws.amazon.com/connect/latest/adminguide/cancel-current-service.html), page body (two sentences). Checked 2026-09-25.
[^27]: Amazon Connect does not allow anonymous calls, so every queue, including the inbound queue used for agent-initiated external transfers, needs a valid outbound caller ID number or the call fails. Source: [Set up outbound caller ID in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/queues-callerid.html), Outbound parameters: Set in queue > Anonymous caller ID. Checked 2026-09-25.
[^28]: An Amazon Connect instance needs a claimed DID or toll-free phone number to place or receive calls. Source: [Get a local toll-free or DID Connect Customer phone number](https://docs.aws.amazon.com/connect/latest/adminguide/claim-phone-number.html), Get a local toll-free or DID Connect Customer phone number (opening paragraph). Checked 2026-09-25.
[^29]: A claimed or ported Amazon Connect number is attached to a flow on Channels > Phone numbers > Edit Phone number by choosing the flow under Flow / IVR, and only published flows appear in that list. Source: [Attach a claimed or ported phone number to a flow in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/associate-claimed-ported-phone-number-to-flow.html), To associate a claimed or ported phone number with a published flow, steps 2-4. Checked 2026-09-25.
[^30]: Persistent connection is set per agent under Phone > Softphone in user management, works only in Chrome and Edge (not Firefox), and agents cannot turn it off themselves. Source: [Enable persistent connection for Connect Customer agents](https://docs.aws.amazon.com/connect/latest/adminguide/enable-persistent-connection.md), How to configure persistent connection for an agent; FAQ. Checked 2026-09-25.
[^31]: A phone number quick connect invokes no flow, so its outbound caller ID cannot be set per transfer and comes from the queue configuration. Source: [Create quick connects in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/quick-connects.html), More examples > External quick connects. Checked 2026-09-25.
[^32]: In most cases the losing carrier, not the customer, picks the date and time of a port to Amazon Connect; a preferred date can be requested in the support case. Source: [How long does it take to port phone numbers to Connect Customer?](https://docs.aws.amazon.com/connect/latest/adminguide/how-long-for-number-porting.html), Can I choose the port date?. Checked 2026-09-25.
[^33]: Porting numbers from outside the US and Canada to Amazon Connect takes two to six months to complete. Source: [How long does it take to port phone numbers to Connect Customer?](https://docs.aws.amazon.com/connect/latest/adminguide/how-long-for-number-porting.html), Outside the US and Canada. Checked 2026-09-25.
[^34]: A port request for US DID or toll-free numbers cannot be submitted more than 30 days before the porting date. Source: [How long does it take to port phone numbers to Connect Customer?](https://docs.aws.amazon.com/connect/latest/adminguide/how-long-for-number-porting.html), Important box at top of page. Checked 2026-09-25.
[^35]: Porting US or Canadian numbers to Amazon Connect typically takes two to four weeks after portability is verified and all documents are submitted correctly. Source: [How long does it take to port phone numbers to Connect Customer?](https://docs.aws.amazon.com/connect/latest/adminguide/how-long-for-number-porting.html), Inside the US and Canada. Checked 2026-09-25.
[^36]: On the PSTN return path the only context documented as reaching the Unified CM side is the caller ID; the Transfer to phone number block page documents no field for passing other call data (inferred). Source: [Flow block in Connect Customer: Transfer to phone number](https://docs.aws.amazon.com/connect/latest/adminguide/transfer-to-phone-number.html), Properties (whole section). Checked 2026-09-25.
[^37]: A phone number quick connect's number is entered starting with the country code, and outbound calls also need an outbound caller ID number set on the queue. Source: [Create quick connects in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/quick-connects.html), Example: Create a phone number quick connect to a mobile phone. Checked 2026-09-25.
[^38]: Agents see only the quick connects attached to the queues in their routing profile, including the default outbound queue, so a quick connect must be added to a queue on the Edit queue page. Source: [Create quick connects in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/quick-connects.html), Step 2: Enable agents to see quick connects (and Tip). Checked 2026-09-25.
[^39]: An Amazon Connect phone number cannot be claimed again after it is released. Source: [Get a local toll-free or DID Connect Customer phone number](https://docs.aws.amazon.com/connect/latest/adminguide/claim-phone-number.html), How many phone numbers you can claim. Checked 2026-09-25.
[^40]: The independent guide says Amazon Connect contact attributes can be inserted into custom SIP headers on transfers so the Cisco side keeps customer context (inferred). Source: [A Technical Guide to Amazon Connect & Cisco CUCM Integration](https://intelligentvisibility.com/guide-amazon-connect-cisco-cucm-integration), Data Passing Mechanisms > Context-Aware Transfers. Checked 2026-09-25.
[^41]: Community answers disagree on native SIP support: one says external voice transfer provides native SIP transfers out of Amazon Connect, and a later one says inbound SIP trunking from on-premises systems into Amazon Connect is not publicly supported (field report). Source: [Does AWS connect support SIP transfers natively?](https://repost.aws/questions/QUhjj_qhY9S_29EUf6npqDpg/does-aws-connect-support-sip-transfers-natively), answers 1 and 2. Checked 2026-09-25.
[^42]: The external voice transfer material reached describes Amazon Connect handing calls to another voice system; none of it documents Unified CM (or any PBX) sending new calls into Amazon Connect over a SIP trunk (inferred). Source: [Amazon Connect now supports external voice transfers](https://aws-news.com/article/2024-12-02-amazon-connect-now-supports-external-voice-transfers), announcement (whole text). Checked 2026-09-25.
[^43]: AWS recommends the domain allowlist (Option 1) for CCP connectivity and testing it with more than 200 calls; an error rate above 2 percent suggests a proxy problem and a move to the IP-range allowlist (Option 2). Source: [Set up your network to use the Connect Customer Contact Control Panel (CCP)](https://docs.aws.amazon.com/connect/latest/adminguide/ccp-networking.html), Option 1 (recommended), second paragraph. Checked 2026-09-25.
[^44]: The CCP softphone needs outbound UDP 3478 to the Region's TurnNlb endpoints; without it agents see Failed to establish softphone connection and miss calls. Source: [Set up your network to use the Connect Customer Contact Control Panel (CCP)](https://docs.aws.amazon.com/connect/latest/adminguide/ccp-networking.html), Option 1 table (TurnNlb row); Allow DNS resolution for softphones. Checked 2026-09-25.
[^45]: The same independent guide says SIP signalling to Amazon Connect over the public internet must use TLS and media must use SRTP (inferred). Source: [A Technical Guide to Amazon Connect & Cisco CUCM Integration](https://intelligentvisibility.com/guide-amazon-connect-cisco-cucm-integration), CUBE Technical Requirements > Encryption Standards. Checked 2026-09-25.
[^46]: The independent guide says CUBE must transcode between G.711/G.729 and Opus for Amazon Connect calls (inferred). Source: [A Technical Guide to Amazon Connect & Cisco CUCM Integration](https://intelligentvisibility.com/guide-amazon-connect-cisco-cucm-integration), Codec Handling table. Checked 2026-09-25.
[^47]: For a transfer made while the agent is on a call, caller ID comes from the inbound queue that handled the call and the outbound whisper flow cannot override it; to control it, use a Transfer to phone number block with an explicit caller ID. Source: [Set up outbound caller ID in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/queues-callerid.html), How outbound parameters are selected > Note. Checked 2026-09-25.
[^48]: To set up phone number transfers, create a phone number quick connect (it needs no flow), add it to a queue used for incoming contacts, and make sure that queue is in the transferring agents' routing profile. Source: [Set up contact transfers in Connect Customer](https://docs.aws.amazon.com/connect/latest/adminguide/transfer.html), Overview of steps. Checked 2026-09-25.
[^49]: The Transfer to phone number block can be used in Inbound, Customer Queue, Transfer to Agent and Transfer to Queue flows. Source: [Flow block in Connect Customer: Transfer to phone number](https://docs.aws.amazon.com/connect/latest/adminguide/transfer-to-phone-number.html), Flow types. Checked 2026-09-25.
[^50]: The Amazon Connect Transfer to phone number flow block handles voice only, takes chat, task and email contacts down its Error branch, and has Success, Call Failed, Timeout and Error branches. Source: [Flow block in Connect Customer: Transfer to phone number](https://docs.aws.amazon.com/connect/latest/adminguide/transfer-to-phone-number.html), Supported channels; Configured block. Checked 2026-09-25.
[^51]: When the Transfer to phone number block has no custom caller ID, the external party sees the customer's own caller ID. Source: [Flow block in Connect Customer: Transfer to phone number](https://docs.aws.amazon.com/connect/latest/adminguide/transfer-to-phone-number.html), Properties > Caller ID name > Note (final paragraph). Checked 2026-09-25.
[^52]: A transfer to a phone number fails unless the instance is allowed to call the destination country; countries are added through a service quota increase request. Source: [Flow block in Connect Customer: Transfer to phone number](https://docs.aws.amazon.com/connect/latest/adminguide/transfer-to-phone-number.html), Configuration tips (first two bullets). Checked 2026-09-25.
[^53]: The block's Resume flow after disconnect option returns the caller to the Amazon Connect flow only when the external party hangs up; if the customer hangs up, the whole call ends. Source: [Flow block in Connect Customer: Transfer to phone number](https://docs.aws.amazon.com/connect/latest/adminguide/transfer-to-phone-number.html), Properties > Resume flow after disconnect. Checked 2026-09-25.
[^54]: In the Amazon Connect admin website, numbers are claimed from Channels, Phone numbers, Claim a number, choosing a toll-free or DID number, and can be attached to a flow in the Flow / IVR field before saving. Source: [Get a local toll-free or DID Connect Customer phone number](https://docs.aws.amazon.com/connect/latest/adminguide/claim-phone-number.html), Claim a number for your contact center, steps 1-5. Checked 2026-09-25.
[^55]: After you release a claimed Amazon Connect number you cannot claim the same number again. Source: [Get a local toll-free or DID Connect Customer phone number](https://docs.aws.amazon.com/connect/latest/adminguide/claim-phone-number.html), How many phone numbers you can claim. Checked 2026-09-25.
[^56]: Number porting must be requested in advance and its duration varies by country and complexity, so Salesforce advises planning it early. Source: [Prepare for a Partner Contact Center (Trailhead unit)](https://trailhead.salesforce.com/content/learn/modules/service-cloud-voice-setup-quick-look/prepare-for-a-voice-implementation), Implementation Planning / Key Considerations. Checked 2026-09-25.
[^57]: CUBE is a back-to-back user agent that terminates and originates SIP signaling and RTP/RTCP media and connects enterprise VoIP networks to ITSPs. Source: [Cisco Unified Border Element Configuration Guide - Cisco IOS XE 17.6 Onwards - Overview of Cisco Unified Border Element](https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/ios-xe/config/ios-xe-book/voi-cube-overview.html), Overview of Cisco Unified Border Element, opening sections. Checked 2026-09-25.
[^58]: CUBE provides address and port translation for topology hiding, DTMF, fax, modem and codec transcoding interworking, and delayed-offer to early-offer conversion. Source: [Cisco Unified Border Element Configuration Guide - Cisco IOS XE 17.6 Onwards - Overview of Cisco Unified Border Element](https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/ios-xe/config/ios-xe-book/voi-cube-overview.html), Overview of Cisco Unified Border Element, feature list. Checked 2026-09-25.