Inviting a SIP/H.323 room system to a meeting in Zoom

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

Using the Zoom Client’s public IP address or SIP URI, you can make calls to an H.323 or SIP room system via the H.323/SIP Room Connector add-on.

Prerequisites for inviting a SIP/H.323 room system to a meeting

  • It is recommended that the host account is at least a Pro level
  • At least one subscription for a Room Connector port (one port will be counted as one device that is connected via call-out).
  • A device must have an external, public IP address or a SIP URI that can be accessed from the Internet
  • Your network firewall must be configured to allow external calls to the device as well as internal calls to the device
  • The use of Zoom’s call-out feature requires Zoom version 3.5 or higher in order to function properly.

How to invite a H.323/SIP room system to a meeting

Windows | macOS | Linux

  1. Start the Zoom Desktop Client and sign in with your Zoom account.
  2. Start a meeting or join one already in progress.
  3. The meeting controls can be accessed by clicking on Participants.
  4. On the participants panel, you will find a button called Invite at the bottom.
  5. Select the Room System tab on the left side of the screen.
  6. To make a call out, click on the Call Out tab.
  7. If a device is a H.323 or SIP type device, you will need to enter its IP address or SIP URI, or choose a device from the Directory of H.323/SIP Rooms.
  8. If you would like to make a H.323 or SIP call, you will need to first select the type of call you wish to make.
  9. To make a call, click the Call button.
  10. The Show Keypad option is available if you need to enter digits during the call-out (e.g. meeting ID) if you require it.
  11. With the help of the pop-up keypad, you can enter numbers into the field.

Android | iOS

How to set the call speed for call-out to H.323 devices

Call-out speed is set by default to 1920kbps (maximum speed). The Zoom call-out feature allows you to set the speed of the call when you are using it, such as the following examples illustrate how to set the speed of the Zoom call-out feature.

[IP address]; speed = 768 kbps

This IP address is [IP address]; speed is 768000

It is a combination of [IP address] and [E.164 address]; speed is 1472k

How to send DTMF tones in a call-out to H.323 devices

DTMF tones can be sent by entering the party number, conference number, or e.164 address in the Callout dial string when connecting to hardware such as Gatekeepers, MCUs, or other H.323/SIP components that require a party number, conference number, or e.164 address for authentication.

DTMF = [DTMF tones];IP = [IP address]

  • There is a 1 second interval between DTMF tones
  • By entering a “,” in the middle of the DTMF tone, a pause of one second will be added

The following are some examples:

The IP address of the device is
The conference number is 15562.
The password is 622.

You can dial the following number:;dtmf=15562#,,622#

  • The IP address that is dialed is
  • The DTMF tones we send are ‘1’ ‘5’ ‘5’ ‘6’ ‘2’ ‘#’ pause pause ‘6’ ‘2’ ‘2’ ‘#’ DTMF tones we send are ‘1’ ‘5’ ‘5’

If you would like to add DTMF tones along with a call speed (using the example above):

I would like to have a call-speed of 768 kbps on my line

You can dial the following number:;dtmf=15562#,,622#;speed=768k