In a SIP point-to-point configuration, a Grandstream GXP 16xx series IP phone and a CyberData device can place calls to each other on the same network without a SIP server.
CyberData Device Configuration
For your reference, instructions on point-to-point configuration are provided in the Operations Guide of every CyberData SIP-enabled device.
To configure point-to-point on a CyberData device, log into the web interface and follow these steps:
1. Disable 'Register with a SIP server' on the SIP configuration page
2. Enter the IP address of the Grandstream phone into the 'Dial Out Extension' field on the SIP configuration page for outbound dialing
3. Save and Reboot to store changes
Grandstream GXP 16xx Series Phone Configuration
Unless you are planning to use Quick IP Call Mode for shortcut keys (recommended), no configuration changes are needed to enable Point-to-Point calls to a CyberData device.
Dialing from a Grandstream GXP 16xx Series Phone
1. Press MENU button to bring up main menu.
2. Select "Direct IP Call" using the navigation arrow keys.
3. Press MENU to enter the Direct IP Call mode.
4. Input the IP address and SIP Port number of the CyberData device (Please see example below).
5. Press "OK" softkey to dial. Wait for about 4 seconds and the phone will initiate the call.
For example, if the IP address of the CyberData device is 10.10.1.222 and the port is 5060 (i.e., 10.10.1.222:5060), input the following: 10*10*1*222#5060. The * key represents the dot (.), the # key represents colon (:).
Quick IP Call Mode
Grandstream GXP 16xx Series phones also support Quick IP Call mode. This enables the phone to make direct IP calls using only the last few digits (last octet) of the CyberData device’s IP address. This is possible only if both the phone and CyberData device are under the same LAN. Controlled static IP usage is recommended.
To enable Quick IP Call Mode, go to Grandstream phone's Web GUI→Settings→Call Features, set "Use Quick IP - call mode" to "Yes". Clicking on "Save and Apply" on the bottom of Web GUI page to take the change. To make Quick IP Call, take the phone off hook first. Then dial #xxx where x is 0-9 and xxx←255. Press # or SEND and a point-to-point call to aaa.bbb.ccc.XXX will be completed. "aaa.bbb.ccc" is from the local IP address regardless of subnet mask. The number #xx or #x are also valid. The leading 0 is not required (but it's OK).
CyberData v3.1 SIP Paging Server tested using firmware version 12.
Any CyberData SIP-enabled device can be configured in the same manner for point-to-point calls.
Grandstream documentation that was used for reference: http://www.grandstream.com/sites/default/files/Resources/gxp16xx_user_guide.pdf