0x01EF Initial UDP Port Number

Specifies the first UDP port number that will be used for receiving the RFC 2833 stream from an endpoint. The CSP increments the port number beyond this "seed" by two for every new call. The port number rolls over to the initial value once all the configured ports are exhausted.

You specify the number of UDP ports in the Number of UDP Ports 0x01F0.

Used in:
VoIP Protocol Configure message
VoIP Protocol Query message

Byte | Description
0, 1 | Tag 0x01EF
2, 3 | Length 0x0002
4, 5 | Value[0,1] Initial port number above 1024. 0x0400 - 0x2710 (1024-10,000) 0x2710 is the default

Voice over Internet Protocol. The delivery of voice information in digital form in discrete packets rather than in the traditional circuit-committed protocols of the public-switched telephone network (PSTN).