WarmTransfer
legacy adjacent · published

Analog gateways ATA and paging devices

Verified 2026-09-24 · 60 sources · tier 1–3

Analog Telephony Adapters (ATAs) and analog gateways connect legacy analog endpoints—such as standard telephones, fax machines, overhead paging systems, and elevator communicators—to cloud telephony platforms 28​52​20. Depending on the platform, these devices interface through cloud-managed SIP gateway services, native platform registrations, or local Session Border Controllers (SBCs) 35​39.

Direct Routing and SBC Interworking

To connect analog devices to Microsoft Teams Phone Direct Routing, an ATA is required, and the ATA must be supported by the certified SBC vendor 30. In Direct Routing deployments, signaling and media from the analog device flow through the ATA to the SBC, and the SBC routes the call to a Teams endpoint or to the PSTN based on its internal routing table 35. Microsoft defines an analog device for Direct Routing as any device that can send DTMF digits to place a call, naming analog phones, fax machines, and overhead pagers as examples 28. Microsoft defers ATA-to-SBC configuration to the SBC manufacturer's guide and links AudioCodes, Ribbon, and Oracle documentation 34.

Microsoft's example configuration workflow for analog devices on Direct Routing involves 7 steps: connect the SBC, create the PSTN usage, create a voice route tied to that usage, create a voice routing policy with the usage, enable the online user, grant the policy to the user, and create a voice route for the analog device 32. In this example, the Set-CsUser and Grant-CsOnlineVoiceRoutingPolicy steps are run for each Teams user, excluding ATA device users 31. Calls to an analog device behind an ATA are reached by an online voice route (New-CsOnlineVoiceRoute) whose number pattern matches the analog device numbers and whose gateway list points at the SBC 29. Microsoft says to run it per analog device or use a suitable pattern in an earlier route 29. Furthermore, analog phones connected to an ATA on Direct Routing are not searchable from Teams, requiring Teams users to manually enter the device's phone number to call it 33.

Cloud Platform Native and SIP Gateway Deployment

ATAs connect non-IP devices such as analog phones, fax machines, and overhead paging systems so they act as Webex Calling devices 52, while Direct Routing routes the call through an SBC 35 and native platform registration handles SIP registration paths 39.

Platform Supported Models Interface & Port Constraints
Microsoft Teams SIP Gateway Cisco ATA191-MPP, ATA192-MPP; Poly ATA 400, ATA 402, OBi 300, OBi 302; AudioCodes MP series; 2N Lift IP 2.0; Algo 8301, 8373, 8305 23​24​22​20​21 On Teams SIP Gateway several AudioCodes MediaPack ATAs expose fewer than all ports: MP114 3 of 4, MP118 6 of 8 and MP124 18 of 24, while MP112, MP1288 and the MP50x models have all ports available 22. Static location only 26.
Cisco Webex Calling ATA191 Multiplatform, ATA192 Multiplatform, VG400 ATA, VG410 ATA, VG420 ATA; Poly ATA 400, ATA 402; AudioCodes MP-124E, MP-1288, MP-202, MP-204, MP-504, MP-508, MP-516, MP-524, MP-532 53​56 AudioCodes MP-124E supports only 17 ports because of the platform's mandatory encryption requirements 54. Webex Calling does not support modems 55.
Zoom Phone Poly OBi30X, OBi508, ATA40X 60 In Zoom Phone, ATA ports can be assigned to users or common areas, only extensions at the same site as the device can be selected, and emergency addresses must be at the same site as the port owners 57.

Teams users must have a phone number with PSTN calling enabled to use SIP Gateway, and SIP Gateway is not yet available for DoD 25. Cisco ATA191-MPP and ATA192-MPP appear with minimum firmware 11.2.2MPP and approved firmware 11-3-1MPP 23. Poly ATA 400 and ATA 402 are listed with firmware 4.0.1.6480, and Poly OBi 300 and OBi 302 with minimum 3.2.4.8441 and approved firmware 3.2.5.8732 24. The 2N Lift IP 2.0 elevator communicator appears with firmware 2.46.1 20. On Teams SIP Gateway the listed ATAs and Algo paging adapters carry footnote 3, meaning they support only static location, not dynamic location discovery 26.

Managing ATA devices in Zoom Phone requires the device to be added and provisioned and a Zoom Workplace license with Phone or a standalone Zoom Phone calling plan 58. In Zoom Phone, ATA ports can be assigned to users or common areas, only extensions at the same site as the device can be selected, and emergency addresses must be at the same site as the port owners 57.

High-Density Gateways: Cisco VG4xx Series

Cisco describes ATAs on Webex Calling as connecting non-IP devices such as analog phones, fax machines and overhead paging systems so they act as Webex Calling devices 52. For Webex Calling, the VG400 ATA comes with 2, 4, 6 or 8 FXS ports, the VG410 with 24 or 48, and the VG420 with 84, 132 or 144, with 4- or 8-port expansion available on the 84 and 132 port VG420 models 48. Cisco lists uck9, securityk9 and webex_calling licenses as required on the VG4xx device for Webex Calling 41. Users with a Webex Calling Standard license cannot be assigned to VG4xx device ports 46.

A cloud-registered VG400 downloads its SIP configuration from Control Hub over HTTPS, after which each configured FXS port registers to Webex Calling as a SIP line 39. Communication between a cloud-registered VG400 and Webex Calling is encrypted, with SIP signaling over TLS and media over SRTP 40. Once a VG400 is registered to Webex Calling, its CLI and web UI are locked and further provisioning is managed through Control Hub 36. VG4xx ATA ports are numbered from 0 in Control Hub, unlike other ATAs whose ports are numbered from 1 50. The workspace or user selected when adding a VG4xx ATA in Control Hub is permanently assigned to ATA port 1 49. Virtual lines cannot be assigned to a VG4xx ATA on Webex Calling, and a workspace or user may occupy only one line of a given VG4xx ATA 47. Extensions assigned to VG4xx ports must have at least 4 digits to register with the Webex platform 42.

VG400 FXS ports support FXS-E with 35 mA loop current and loop lengths up to 11,000 feet (3,400 m) on 26 AWG wire 38. Cisco's VG4xx Control Hub article lists IOS XE 17.18.1a as the supported firmware and states that site survivability support requires VG4xx IOS XE 17.16.1 44. FXO and ISDN interfaces on VG4xx gateways are not currently supported for use with Webex Calling 45.

Fax and Telephony Adapters

The Cisco ATA 191 and ATA 192 each have two RJ-11 FXS ports for standard analog phone devices 12. Cisco says a fax machine should be connected directly to the ATA, with no extension connected to the fax machine and no splitter 8. To reduce fax failures through the ATA 191/192, Cisco advises using the fax machine's overseas mode if available, otherwise setting the transmission speed to low 9. Cisco's fax troubleshooting for the ATA 191/192 says to verify the fax machine is set to a speed between 7200 and 14400 and to run test faxes in a controlled environment while monitoring network statistics 10. Cisco warns that fax machines and modems may not work optimally through the ATA 191/192 and recommends continuing to use a dedicated PSTN line for best fax and modem performance 7.

The ATA 191 Multiplatform datasheet lists G.711 a-law, G.711 mu-law, G.729a, G.729ab and G.726 audio codecs, and lists real-time Group 3 fax over IP via T.38 fax relay and fax pass-through via G.711 5​6. On the ATA 191/192, if a T.38 call cannot be set up the call automatically reverts to G.711 fallback 11. Cisco's VG400 Webex Calling whitepaper lists SIP-based T.38 fax relay and G.711 fax passthrough among supported call features, and for fax machines on a VG4xx port in Webex Calling, Cisco instructs enabling T.38 compression to override the default audio codec 37​43. The in-force edition of ITU-T Recommendation T.38, Procedures for real-time Group 3 facsimile communication over IP networks, is T.38 (11/2015); editions from 1998 through 2010 are superseded 27. RFC 3362 registers the image/t38 media sub-type, whose encoding is defined by ITU-T T.38, for use as an SDP media descriptor indicating a T.38 stream 19.

Zoom's fax setup for Poly OBi30X, OBi508 and ATA40X on Zoom Phone disables T.38 (T38Enable=Disabled) and uses G.711 passthrough (FaxPassThroughCodec G711U or G711A), with call waiting and conferencing disabled and UseForFaxOnly enabled 60. Zoom states fax over VoIP on Zoom Phone has known limitations and recommends that businesses heavily dependent on large multi-page faxes keep an analog line and traditional fax machine 59. WarmTransfer's reading of the sources is that across Cisco and Zoom documentation, fax through a cloud-registered ATA is treated as best-effort: both vendors recommend retaining a dedicated analog or PSTN line where fax reliability matters 14.

NFON's October 2022 'End of Sale' notice for the Cisco ATA 191 announces that NFON is ending its own sale of the device, with support for NFON customers continuing to end of 2024; it is a provider notice, not a Cisco lifecycle announcement 18.

Paging and Specialized Endpoints

Algo states that where a paging amplifier was connected to an ATA FXS port through a telephone answering device, the 8301 replaces the answering device and eliminates the need for an FXS port or ATA 4. Teams SIP Gateway lists the Algo 8301, 8373 and 8305 as compatible paging adapters, and Microsoft directs support queries for listed Algo endpoints to Algo 21. Webex Calling lists the Algo 8301 and 8373 as supported pagers, alongside Algo speakers, strobes and door phones and devices from 2N, Grandstream, CyberData and Axis 51.

The Algo 8301 registers SIP credentials for a Page extension, which auto-answers for live paging, and a Ring extension, which detects inbound calls without answering and plays pre-recorded announcements 3. The Algo 8301 line output connects to an amplifier's audio input with an input impedance between 600 ohm and 10 kohm 1. The Algo 8301 supports multicast paging as transmitter or receiver with 9 basic zones expandable to 50, plus an NTP-synchronised scheduler for tones and announcements 2.

The FCC adopted its network modernization Report and Order, FCC 26-19, on 26 March 2026 (released 27 March 2026) in WC Docket Nos. 25-209 and 25-208, overhauling section 214 technology-transition discontinuance rules 16. FCC 26-19 grants carriers blanket section 214(a) authority to grandfather legacy voice services, lower-speed data services and interconnected VoIP provisioned over copper 17.

See also

Applicability

Applies to: Microsoft Teams Phone Direct Routing, Cisco Webex Calling, Microsoft Teams SIP Gateway, Cisco VG400 on Webex Calling, Zoom Phone with Poly OBi, Zoom Phone, Cisco VG400 VG410 VG420 on Webex Calling, Cisco VG400, Cisco ATA 191, Cisco ATA 191 Multiplatform, ITU-T Recommendation T.38, IETF RFC 3362, Webex Calling, NFON hardware portfolio, Algo 8301 Paging Adapter, and FCC 47 CFR Part 63. Deployments: on-premises, multi-tenant, and carrier. Sources checked 2026-09-24. The European region is specifically cited regarding NFON's October 2022 End of Sale notice for the Cisco ATA 191 18. United States jurisdiction applies specifically to FCC Order 26-19 carrier discontinuance rules adopted on 26 March 2026 16​17. Software releases covered in the claims include Cisco IOS XE 17.18.1a and VG4xx IOS XE 17.16.1 for VG4xx gateways 44, Cisco Multiplatform firmware 11.2.2MPP and 11-3-1MPP 23, Poly firmware 4.0.1.6480, 3.2.4.8441, and 3.2.5.8732 24, 2N Lift IP 2.0 firmware 2.46.1 20, and ITU-T Recommendation T.38 (11/2015) 27.

What remains uncertain

  • Specific paragraph numbers and text in FCC 26-19 covering replacement categories, G.711 alarm conditions, and notice timing are not covered by the sources below.
  • Compliance details for Kari's Law and RAY BAUM'S Act regarding dispatchable location for analog stations behind ATAs on cloud MLTS systems are not covered by the sources below.
  • Cisco's manufacturer lifecycle status and official End of Sale or End of Life notices for the ATA 191 and ATA 192 are not covered by the sources below.
  • Whether Microsoft Teams SIP Gateway supports fax transmission or T.38 relay on listed ATAs is not covered by the sources below.
  • Alarm panel Contact ID and modem signaling through ATAs, given Webex Calling's explicit lack of modem support, are not covered by the sources below.
  • Cellular POTS-replacement appliance integration for elevators and alarms following copper discontinuance is not covered by the sources below.
  • The complete list of supported ATA hardware models and provisioning modes on Zoom Phone is not covered by the sources below.
  • Integrating FXO ports and analog PSTN trunks into Webex Calling via Local Gateways rather than VG4xx models is not covered by the sources below.

See also

Depends on

  • Fax and T.38 in cloud calling — Inbound relationship recorded in corpus: fax survives migrations through analog gateways; this packet records vendor T.38 and G.711 passthrough guidance for ATAs

Explains

Referenced by

Sources

  1. 1
    The Algo 8301 line output connects to an amplifier's audio input with an input impedance between 600 ohm and 10 kohm.
    8301 Paging Adapter & Scheduler User Guide · Amplifier connection section · Checked 2026-09-24
  2. 2
    The Algo 8301 supports multicast paging as transmitter or receiver with nine basic zones expandable to 50, plus an NTP-synchronised scheduler for tones and announcements.
    8301 Paging Adapter & Scheduler User Guide · Multicast; Scheduler · Checked 2026-09-24
  3. 3
    The Algo 8301 registers SIP credentials for a Page extension, which auto-answers for live paging, and a Ring extension, which detects inbound calls without answering and plays pre-recorded announcements.
    8301 Paging Adapter & Scheduler User Guide · SIP settings, Page and Ring extensions · Checked 2026-09-24
  4. 4
    Algo states that where a paging amplifier was connected to an ATA FXS port through a telephone answering device, the 8301 replaces the answering device and eliminates the need for an FXS port or ATA.
    8301 Paging Adapter & Scheduler User Guide · Amplifier connection section · Checked 2026-09-24
  5. 5
    The ATA 191 Multiplatform datasheet lists G.711 a-law, G.711 mu-law, G.729a, G.729ab and G.726 audio codecs.
    Cisco ATA 191 Multiplatform Analog Telephone Adapter Data Sheet · Specifications, audio codecs · Checked 2026-09-24
  6. 6
    The Cisco ATA 191 Multiplatform datasheet lists real-time Group 3 fax over IP via T.38 fax relay and fax pass-through via G.711.
    Cisco ATA 191 Multiplatform Analog Telephone Adapter Data Sheet · Specifications, fax · Checked 2026-09-24
  7. 7
    Cisco warns that fax machines and modems may not work optimally through the ATA 191/192 and recommends continuing to use a dedicated PSTN line for best fax and modem performance.
    Get started with your Cisco ATA 191 and 192 · Your New Cisco ATA 191 and 192, limitation statement · Checked 2026-09-24
  8. 8
    Cisco says a fax machine should be connected directly to the ATA, with no extension connected to the fax machine and no splitter.
    Get started with your Cisco ATA 191 and 192 · Devices Associated with Your ATA, Fax Machines · Checked 2026-09-24
  9. 9
    To reduce fax failures through the ATA 191/192, Cisco advises using the fax machine's overseas mode if available, otherwise setting the transmission speed to low.
    Get started with your Cisco ATA 191 and 192 · Devices Associated with Your ATA, Fax Machines · Checked 2026-09-24
  10. 10
    Cisco's fax troubleshooting for the ATA 191/192 says to verify the fax machine is set to a speed between 7200 and 14400 and to run test faxes in a controlled environment while monitoring network statistics.
    Cisco ATA 191 and ATA 192 Analog Telephone Adapter Administration Guide for Multiplatform Firmware - Advanced Options for Phone Services · Troubleshoot Your Fax · Checked 2026-09-24
  11. 11
    On the ATA 191/192, if a T.38 call cannot be set up the call automatically reverts to G.711 fallback.
    Cisco ATA 191 and ATA 192 Analog Telephone Adapter Administration Guide for Multiplatform Firmware - Advanced Options for Phone Services · Optimize Fax Completion Rates · Checked 2026-09-24
  12. 12
    The Cisco ATA 191 and ATA 192 each have two RJ-11 FXS ports for standard analog phone devices.
    Get started with your Cisco ATA 191 and 192 · Cisco ATA 191 and ATA 192 Hardware · Checked 2026-09-24
  13. 13
    As of 2026-09-24 Cisco's ATA 190 Series end-of-life listing shows only two notices: the ATA 190 (17 Sep 2018) and the Spark Call 1 Port Analog Telephone Adapter (14 Oct 2020); no ATA 191 or ATA 192 notice appears.
    Cisco ATA 190 Series Analog Telephone Adapters - End-of-Life and End-of-Sale Notices · Notice list · Checked 2026-09-24
  14. 14
    Across Cisco and Zoom documentation, fax through a cloud-registered ATA is treated as best-effort: both vendors recommend retaining a dedicated analog or PSTN line where fax reliability matters.inferred
    Get started with your Cisco ATA 191 and 192 · Your New Cisco ATA 191 and 192, limitation statement · Checked 2026-09-24
  15. 15
    FCC 26-19 applies the 31-day automatic grant period to all discontinuance applications regardless of dominant or non-dominant status, and carriers must notify customers no later than the date they file.
    Accelerating Network Modernization; Reducing Barriers to Network Improvements and Service Changes, Report and Order (FCC 26-19) · Paragraphs 30 and 85; rule 63.71(f)(1) (paragraph numbers unverified) · Checked 2026-09-24
  16. 16
    The FCC adopted its network modernization Report and Order, FCC 26-19, on 26 March 2026 (released 27 March 2026) in WC Docket Nos. 25-209 and 25-208, overhauling section 214 technology-transition discontinuance rules.
    FCC Takes Action to Speed Up Rollout of Modern, High-Speed Networks · News release headline and first paragraphs · Checked 2026-09-24
  17. 17
    FCC 26-19 grants carriers blanket section 214(a) authority to grandfather legacy voice services, lower-speed data services and interconnected VoIP provisioned over copper.
    FCC Takes Action to Speed Up Rollout of Modern, High-Speed Networks · News release, list of actions · Checked 2026-09-24
  18. 18
    NFON's October 2022 'End of Sale' notice for the Cisco ATA 191 announces that NFON is ending its own sale of the device, with support for NFON customers continuing to end of 2024; it is a provider notice, not a Cisco lifecycle announcement.
    End of Sale (EOS) Announcement – Cisco ATA 191 · Page body · Checked 2026-09-24
  19. 19
    RFC 3362 registers the image/t38 media sub-type, whose encoding is defined by ITU-T T.38, for use as an SDP media descriptor indicating a T.38 stream.
    Real-time Facsimile (T.38) - image/t38 MIME Sub-type Registration · Abstract; Section 3.1 · Checked 2026-09-24
  20. 20
    The 2N Lift IP 2.0 elevator communicator appears in the Teams SIP Gateway compatible device list with firmware 2.46.1.
    Plan SIP Gateway · Compatible devices table, 2N rows, Lift IP 2.0 · Checked 2026-09-24
  21. 21
    Teams SIP Gateway lists the Algo 8301, 8373 and 8305 as compatible paging adapters, and Microsoft directs support queries for listed Algo endpoints to Algo.
    Plan SIP Gateway · Compatible devices table, Algo rows; Note on Algo support queries · Checked 2026-09-24
  22. 22
    On Teams SIP Gateway several AudioCodes MediaPack ATAs expose fewer than all ports: MP114 3 of 4, MP118 6 of 8 and MP124 18 of 24, while MP112, MP1288 and the MP50x models have all ports available.
    Plan SIP Gateway · Compatible devices table, AudioCodes MP rows, Remarks column · Checked 2026-09-24
  23. 23
    Teams SIP Gateway lists Cisco ATA191-MPP and ATA192-MPP as compatible devices with minimum firmware 11.2.2MPP and approved firmware 11-3-1MPP.
    Plan SIP Gateway · Compatible devices table, Cisco rows ATA191-MPP and ATA192-MPP · Checked 2026-09-24
  24. 24
    Teams SIP Gateway lists Poly ATA 400 and ATA 402 (firmware 4.0.1.6480) and Poly OBi 300 and OBi 302 (minimum 3.2.4.8441, approved 3.2.5.8732) as compatible.
    Plan SIP Gateway · Compatible devices table, Poly rows ATA 400, ATA 402, OBi 300, OBi 302 · Checked 2026-09-24
  25. 25
    Teams users must have a phone number with PSTN calling enabled to use SIP Gateway, and SIP Gateway is not yet available for DoD.
    Plan SIP Gateway · Requirements to use SIP Gateway, first paragraph and Note · Checked 2026-09-24
  26. 26
    On Teams SIP Gateway the listed ATAs (Cisco ATA191/192, Poly ATA 40x and OBi 30x, AudioCodes MP series) and Algo paging adapters carry footnote 3, meaning they support only static location, not dynamic location discovery.
    Plan SIP Gateway · Compatible devices table footnote markers; footnote 3 · Checked 2026-09-24
  27. 27
    The in-force edition of ITU-T Recommendation T.38, Procedures for real-time Group 3 facsimile communication over IP networks, is T.38 (11/2015); editions from 1998 through 2010 are superseded.
    T.38 : Procedures for real-time Group 3 facsimile communication over IP networks · Recommendation page edition list · Checked 2026-09-24
  28. 28
    For Direct Routing, Microsoft defines an analog device as any device that can send DTMF digits to place a call, naming analog phones, fax machines and overhead pagers as examples.
    Direct Routing - Connecting analog devices · Considerations, first bullet · Checked 2026-09-24
  29. 29
    Calls to an analog device behind an ATA are reached by an online voice route (New-CsOnlineVoiceRoute) whose number pattern matches the analog device numbers and whose gateway list points at the SBC; Microsoft says to run it per analog device or use a suitable pattern in an earlier route.
    Direct Routing - Connecting analog devices · Step 7: Create a voice route for an analog device · Checked 2026-09-24
  30. 30
    To connect analog devices to Teams Phone Direct Routing an Analog Telephony Adapter (ATA) is required, and the ATA must be supported by the certified SBC vendor.
    Direct Routing - Connecting analog devices · Introductory paragraph · Checked 2026-09-24
  31. 31
    In Microsoft's Direct Routing analog example, the Set-CsUser and Grant-CsOnlineVoiceRoutingPolicy steps are run for each Teams user excluding ATA device users.
    Direct Routing - Connecting analog devices · Step 5: Enable the online user; Step 6: Assign the voice route policy to a user · Checked 2026-09-24
  32. 32
    Microsoft's example for analog devices on Direct Routing has seven steps: connect the SBC, create the PSTN usage, create a voice route tied to that usage, create a voice routing policy with the usage, enable the online user, grant the policy to the user, and create a voice route for the analog device.
    Direct Routing - Connecting analog devices · Example: How to configure the use of analog devices with Direct Routing; Steps 1-7 · Checked 2026-09-24
  33. 33
    Analog phones connected to an ATA on Direct Routing are not searchable from Teams; Teams users must manually enter the device's phone number to call it.
    Direct Routing - Connecting analog devices · Considerations, second bullet · Checked 2026-09-24
  34. 34
    Microsoft defers the ATA-to-SBC configuration to the SBC manufacturer's guide and links AudioCodes, Ribbon and Oracle documentation.
    Direct Routing - Connecting analog devices · Example section, paragraph after the step list · Checked 2026-09-24
  35. 35
    In Direct Routing, signaling and media from an analog device flow through the ATA to the SBC, and the SBC routes the call to a Teams endpoint or to the PSTN based on its internal routing table.
    Direct Routing - Connecting analog devices · Second introductory paragraph · Checked 2026-09-24
  36. 36
    Once a VG400 is registered to Webex Calling, its CLI and web UI are locked and further provisioning is managed through Control Hub.
    Webex Calling and Cisco VG400 Analog Telephone Adapter Technical Whitepaper · Onboarding Cisco VG400 to Webex Calling · Checked 2026-09-24
  37. 37
    Cisco's VG400 Webex Calling whitepaper lists SIP-based T.38 fax relay and G.711 fax passthrough among supported call features.
    Webex Calling and Cisco VG400 Analog Telephone Adapter Technical Whitepaper · Supported Call Flows · Checked 2026-09-24
  38. 38
    VG400 FXS ports support FXS-E with 35 mA loop current and loop lengths up to 11,000 feet (3,400 m) on 26 AWG wire.
    Webex Calling and Cisco VG400 Analog Telephone Adapter Technical Whitepaper · Cisco VG400 Models · Checked 2026-09-24
  39. 39
    A cloud-registered VG400 downloads its SIP configuration from Control Hub over HTTPS, after which each configured FXS port registers to Webex Calling as a SIP line.
    Webex Calling and Cisco VG400 Analog Telephone Adapter Technical Whitepaper · Onboarding Cisco VG400 to Webex Calling · Checked 2026-09-24
  40. 40
    Communication between a cloud-registered VG400 and Webex Calling is encrypted, with SIP signaling over TLS and media over SRTP.
    Webex Calling and Cisco VG400 Analog Telephone Adapter Technical Whitepaper · Webex Application Security · Checked 2026-09-24
  41. 41
    Cisco lists uck9, securityk9 and webex_calling licenses as required on the VG4xx device for Webex Calling.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Prerequisites, device licenses · Checked 2026-09-24
  42. 42
    Extensions assigned to VG4xx ports must have at least 4 digits to register with the Webex platform.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Limitations · Checked 2026-09-24
  43. 43
    For fax machines on a VG4xx port in Webex Calling, Cisco instructs enabling T.38 compression to override the default audio codec.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Port configuration, fax machines · Checked 2026-09-24
  44. 44
    Cisco's VG4xx Control Hub article lists IOS XE 17.18.1a as the supported firmware and states that site survivability support requires VG4xx IOS XE 17.16.1.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Supported firmware; site survivability note · Checked 2026-09-24
  45. 45
    FXO and ISDN interfaces on VG4xx gateways are not currently supported for use with Webex Calling.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Limitations · Checked 2026-09-24
  46. 46
    Users with a Webex Calling Standard license cannot be assigned to VG4xx device ports.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Licensing and port assignment notes · Checked 2026-09-24
  47. 47
    Virtual lines cannot be assigned to a VG4xx ATA on Webex Calling, and a workspace or user may occupy only one line of a given VG4xx ATA.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Port assignment notes · Checked 2026-09-24
  48. 48
    For Webex Calling, the VG400 ATA comes with 2, 4, 6 or 8 FXS ports, the VG410 with 24 or 48, and the VG420 with 84, 132 or 144, with 4- or 8-port expansion available on the 84 and 132 port VG420 models.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Model overview, port options per model · Checked 2026-09-24
  49. 49
    The workspace or user selected when adding a VG4xx ATA in Control Hub is permanently assigned to ATA port 1.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Port assignment notes · Checked 2026-09-24
  50. 50
    VG4xx ATA ports are numbered from 0 in Control Hub, unlike other ATAs whose ports are numbered from 1.
    Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub · Port assignment notes · Checked 2026-09-24
  51. 51
    Webex Calling lists the Algo 8301 and 8373 as supported pagers, alongside Algo speakers, strobes and door phones and devices from 2N, Grandstream, CyberData and Axis.
    Supported devices for Webex Calling · Paging & Door Phone Devices section · Checked 2026-09-24
  52. 52
    Cisco describes ATAs on Webex Calling as connecting non-IP devices such as analog phones, fax machines and overhead paging systems so they act as Webex Calling devices.
    Supported devices for Webex Calling · Analog Telephone Adapters (ATAs) section, introductory sentence · Checked 2026-09-24
  53. 53
    Webex Calling lists ATA191 Multiplatform, ATA192 Multiplatform, VG400 ATA, VG410 ATA and VG420 ATA as supported Cisco analog telephone adapters.
    Supported devices for Webex Calling · Analog Telephone Adapters (ATAs) section, Cisco ATAs · Checked 2026-09-24
  54. 54
    On Webex Calling the AudioCodes MP-124E supports only 17 ports because of the platform's mandatory encryption requirements.
    Supported devices for Webex Calling · Analog Telephone Adapters (ATAs) section, AudioCodes note · Checked 2026-09-24
  55. 55
    Webex Calling does not support modems.
    Supported devices for Webex Calling · Analog Telephone Adapters (ATAs) section, note · Checked 2026-09-24
  56. 56
    Webex Calling lists Poly ATA 400 and ATA 402 and AudioCodes MP-124E, MP-1288, MP-202, MP-204, MP-504, MP-508, MP-516, MP-524 and MP-532 as supported third-party ATAs.
    Supported devices for Webex Calling · Analog Telephone Adapters (ATAs) section, third-party ATAs · Checked 2026-09-24
  57. 57
    In Zoom Phone, ATA ports can be assigned to users or common areas; only extensions at the same site as the device can be selected, and emergency addresses must be at the same site as the port owners.
    Managing analog telephone adapter (ATA) devices · Assigning ports; limitations · Checked 2026-09-24
  58. 58
    Managing ATA devices in Zoom Phone requires the device to be added and provisioned and a Zoom Workplace license with Phone or a standalone Zoom Phone calling plan.
    Managing analog telephone adapter (ATA) devices · Prerequisites · Checked 2026-09-24
  59. 59
    Zoom states fax over VoIP on Zoom Phone has known limitations and recommends that businesses heavily dependent on large multi-page faxes keep an analog line and traditional fax machine.
    Setting up faxing (Poly OBi series ATA) · Limitations · Checked 2026-09-24
  60. 60
    Zoom's fax setup for Poly OBi30X, OBi508 and ATA40X on Zoom Phone disables T.38 (T38Enable=Disabled) and uses G.711 passthrough (FaxPassThroughCodec G711U or G711A), with call waiting and conferencing disabled and UseForFaxOnly enabled.
    Setting up faxing (Poly OBi series ATA) · Configuration settings · Checked 2026-09-24

Documents

tier 1 standards and regulators

Accelerating Network Modernization; Reducing Barriers to Network Improvements and Service Changes, Report and Order (FCC 26-19)

Federal Communications Commission · 2026-03-27 · accessed 2026-09-24

tier 1 standards and regulators

FCC Takes Action to Speed Up Rollout of Modern, High-Speed Networks

Federal Communications Commission · 2026-03-26 · accessed 2026-09-24

tier 1 standards and regulators

Real-time Facsimile (T.38) - image/t38 MIME Sub-type Registration

IETF · 2002-08-01 · accessed 2026-09-24

tier 1 standards and regulators

T.38 : Procedures for real-time Group 3 facsimile communication over IP networks

ITU-T · 2015-11-01 · accessed 2026-09-24

tier 2 current vendor documentation

8301 Paging Adapter & Scheduler User Guide

Algo Communication Products · 2026-09-12 · accessed 2026-09-24

tier 2 current vendor documentation

Cisco ATA 190 Series Analog Telephone Adapters - End-of-Life and End-of-Sale Notices

Cisco · accessed 2026-09-24

tier 2 current vendor documentation

Cisco ATA 191 and ATA 192 Analog Telephone Adapter Administration Guide for Multiplatform Firmware - Advanced Options for Phone Services

Cisco · 2026-01-30 · accessed 2026-09-24

tier 2 current vendor documentation

Cisco ATA 191 Multiplatform Analog Telephone Adapter Data Sheet

Cisco · 2021-09-03 · accessed 2026-09-24

tier 2 current vendor documentation

Configure your Cisco Voice Gateway VG400, VG410, or VG420 in Control Hub

Cisco · 2026-02-03 · accessed 2026-09-24

tier 2 current vendor documentation

Direct Routing - Connecting analog devices

Microsoft Learn · 2026-09-10 · accessed 2026-09-24

tier 2 current vendor documentation

Get started with your Cisco ATA 191 and 192

Cisco · 2025-11-25 · accessed 2026-09-24

tier 2 current vendor documentation

Managing analog telephone adapter (ATA) devices

Zoom · accessed 2026-09-24

tier 2 current vendor documentation

Plan SIP Gateway

Microsoft · 2025-02-28 · accessed 2026-09-16

tier 2 current vendor documentation

Setting up faxing (Poly OBi series ATA)

Zoom · 2026-09-24 · accessed 2026-09-24

tier 2 current vendor documentation

Supported devices for Webex Calling

Cisco Systems, Inc. (help.webex.com) · 2026-07-20 · accessed 2026-09-16

tier 2 current vendor documentation

Webex Calling and Cisco VG400 Analog Telephone Adapter Technical Whitepaper

Cisco · 2022-01-31 · accessed 2026-09-24

tier 3 vendor-maintained repositories

End of Sale (EOS) Announcement – Cisco ATA 191

NFON · 2022-10-12 · accessed 2026-09-24

Cite this page

APA

WarmTransfer. (2026, September 24). Analog gateways ATA and paging devices. WarmTransfer. https://warmtransfer.net/knowledge/analog-gateways-ata

BibTeX

@misc{warmtransfer-analog-gateways-ata,
  title  = {Analog gateways ATA and paging devices},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/analog-gateways-ata},
  note   = {Verified 2026-09-24}
}