System information

38 221 02-FGB 101 544 Uen H - June 2009
7 Fax Service (W35 only)
To enable Fax support over the WCDMA network, the Ericsson W35 uses
Fax over IP based on SIP (RFC 3261) and the T.38 protocol.
The Ericsson W35 supports G3 fax as specified in ITU-T T.30 Annex A.
Older standards, as G1 and G2, and the newer superG3 (sometimes called
V.34fax) are not supported.
7.1 IMS User Agent
The IMS (SIP) User Agent is associated to the “Phone/Fax” port on the
Ericsson W35. This integrated User Agent controls VoIP sessions and
manages and controls the media streams by using the SIP protocol
towards the SIP Server and Media Gateway.
7.2 IMS Call Server
The IMS User Agent requires access to one or more IMS Call servers (also
called SIP proxy/servers). A list can be created with configuration details for
different SIP server/proxy settings and possibly an outbound proxy.
7.3 Media Codec
The Ericsson W35 supports the following CODECs:
• G.711a-law (used for VoIP)
• G.711u-law (used for VoIP)
• T.38 (used for Fax services).
7.3.1 G.711a-law / GG.711 u-law
The G.711a-law and G.711u-law CODECs are used for VoIP and the
settings include Voice Activity Detection (VAD); enable/disable silence
suppression, and the RTP payload size.
7.3.2 T.38
The T.38 settings are used for Fax and even if the parameter name says
T.38 most of the items are basically T.30 settings.
Depending on radio network characteristics there might be a need for fine
tuning the T.38 parameters.
7.4 Timers
The following fax related timers can be configured in the Ericsson W35.
7.4.1 SIP Timers
Since the delay in the radio network is a little bit longer than in a wired
network, it might be needed to adjust the SIP timers (T1, T2, T4 and