Setting up faxing (Poly OBi series ATA) in Zoom

This post was most recently updated on July 28th, 2022

If you connect an analog telephone adapter from the Poly OBi series to a fax machine (OBi302 or OBi508), you can set up fax support. In addition, this article includes recommendations on how to optimize the transmission rate of a fax machine.

Note: Alternatively, FaxSIPit can be used with Zoom Phone.

This article covers:

  • Limitations of fax over Voice over Internet Protocol (VoIP)
  • How to confirm ATA settings in the Zoom web portal
  • How to set up faxing in the OBi ATA web interface
  • Recommended fax machine settings

Prerequisites for setting up faxing on a Poly OBi series ATA (analog telephone device)

  • Admin or owner privileges on the account
  • License for Zoom Phone
  • OBi302 or OBi508 analog telephone adapter connected to the fax machine that has been provisioned with the Poly OBi series
    Note: In order to find out more about Poly assisted provisioning, please refer to the guide.
  • There should be at least one ATA for each phone user or common area phone with a direct number and a calling package
  • Connecting an analog telephone to the ATA requires a handset/dial pad device to serve as the interface
    Note: There may be a device connected to the ATA, such as a multi-function copier, that does not have a handset or dial pad, but still needs to be connected to the ATA. The ATA’s web interface cannot be accessed using these devices as they are not supported.
  • In the account-level settings of the desk phone, there is an option to enable the Web Interface

Limitations of fax over Voice over Internet Protocol (VoIP)

There are known limitations when it comes to the implementation of fax over VoIP services in terms of faxing. Technology-based limitations and industry-wide limitations are the main sources of these limitations. It is commonly used by Zoom, and several VoIP companies, to send fax over the Internet by using the G.711 standard. In spite of the fact that that standard is considered a reliable standard, many providers are still free to interpret it in their own way, and standardization cannot be achieved end-to-end.

Using an analog terminal adapter (ATA), Zoom offers customers the opportunity to connect a traditional fax machine to the Internet via a fax over VoIP service. The best-effort fax services that we offer to our business customers are very cost-effective and are more than adequate for those who simply need to fax from time to time. If you are looking to find a faxing solution that fits your business needs, we encourage you to assess your faxing needs.

In order to meet the needs of your business, Zoom is committed to providing quality services. Our recommendation depends in large part on whether the faxing of large, multi-page documents is one of your business’s main priorities. In this case, it is highly recommended that you maintain a traditional fax machine and an analog line to ensure reliable and consistent faxing.

How to confirm ATA settings in the Zoom web portal

Before setting up faxing using the ATA’s web interface, you must sign in to the Zoom web portal to confirm a few settings.

Note: If the device has a Common Area Phone license, skip steps 5 to 7. The Common Area Phone license doesn’t support voicemail and call queue membership.

  1. Sign in to the Zoom web portal.
  2. Then click Users & Rooms from the navigation menu.
  3. On the Common Area Phones tab, click the ATA assigned to the common area phone.
  4. If your phone has an OBi ATA attached, click the name of the display name for the phone user or common area phone.
  5. Turn off Voicemail under the Policy tab.
  6. Select User Settings from the menu.
  7. Check the Receive Call Queue Calls option at the bottom of the Membership section.
  8. To view and edit the Desk Phone keys and positions, scroll down to the section and click View & Edit.
  9. The ATA should have a dedicated line.

How to set up faxing in the OBi ATA web interface

  1. Press 1 to obtain the IP address by dialing *** from an analog phone connected to the ATA.
  2. Put the ATA’s IP address into the web browser.
  3. Provisioned devices do not have web interfaces by default. Web Interface must be enabled in the account-level desk phone settings if you are unable to access the phone’s web interface.
  4. The admin password is configured in Zoom’s web portal, so sign in as admin for the username.
  5. The Codec Profile A/B can be found under Codecs.
  6. Set the following parameters under Codec Settings:
    • T38Enable=Disabled
    • FaxPassThroughCodec=G711U (default for North America) or G711A
  7. The SP1 service can be found under Voice Services.
  8. Set the following parameter under Calling Features:
    • MaxSessions=1
  9. Proceed to PHONEx Port by navigating to Physical Interfaces,
  10. Set the following parameters under Calling Features:
    • CallWaitingEnable: Disabled
    • ConferenceCallEnable: Disabled
    • UseForFaxOnly: Enabled
    • DetectFaxPageBreak: Enabled

Fax machine settings

We recommend the following settings for your fax machine. Vendors and models of fax machines differ in these settings. More details on these settings can be found in the documentation provided by your fax machine vendor.

  • The lowest speed or Baud rate for fax transmission is 9600bps.
  • ECM (Error Correction Mode) should be disabled.
  • It is recommended that you disable the compression mode.
  • Low-pass filter the Receive/Transmit Buffer.