3Com V7111 - VCX 4 Channels Analog FXO Media Gateway User Manual page 50

Usually the VCX V7111 FXS Gateway sends up to eight REGISTER messages, for each
port, using the port's phone number on the left side of the SIP URL and the common
Gateway password.
The VCX V7111 FXO Gateway usually registers just once, using the username
parameter in the SIP URL, such as sip: username@sipgatewayname. The username
parameter can be defined in the INI file or from the Embedded Web Server.
It is also possible to configure a separate username and password for each Gateway
port.
Supports the following methods: INVITE, CANCEL, BYE, ACK, REGISTER, OPTIONS,
INFO, and REFER.
Modifying connection parameters for an already established call (re-INVITE).
Working with a Redirect server and handling 3xx responses.
Early Media (supporting 183 Session Progress).
PRACK reliable provisional responses (RFC 3262).
Diversion Header (draft-levy-sip-diversion-05.txt).
Call Transfer supplementary services using REFER, Refer-To, Referred-By, Replaces,
and NOTIFY.
Session Timer (draft-ietf-sip-session-timer-10.txt).
Remote party ID (draft-ietf-sip-privacy-04.txt).
DTMF Payload for DTMF Digits (RFC 2833).
DTMF out of band transfer using INFO method (draft-choudhuri-sip-info-digit-00.txt).
SIP URL: sip:phone_number@IP address (such as 122@10.1.2.4, where 122 is the
phone number of the source or destination) or sip:phone_number@domain name, such
as 122@myproxy.com.
Reliable UDP transport, with retransmissions.
Supported codecs:
G.711 A-law
G.711 µ -law
G.723
G.729A
G.726
NetCoders (from 6.4 through 8.8 Kbps)
Can negotiate codec from a list of given codecs
50 3Com VCX V7111 VoIP SIP Gateways User Manual