Thread: Fax issues
View Single Post
Old 04-11-2011, 04:54 AM
rsuresh rsuresh is offline
Aspiring Member
Join Date: Apr 2010
Location: Hyderabad, India
Posts: 1
rsuresh has 10 reputation points
Default My recommendations

Hi Baele,

Change in codecs wont really help because the codecs you see on the ip-codec-set form are audio codecs used for audio calls. For Fax-Over-IP calls, the CM looks at the fax mode you have set in page 2 of the ip-codec-set form -

change ip-codec-set 1 Pag
IP Codec Set
Allow Direct-IP Multimedia? n

Mode Redundancy
->FAX t.38-standard 0
Modem off 0
Clear-channel n 0

There are 3 fax modes - T.38, Relay and Pass-Through. T.38 is popular when integrating with third party systems (MM Fax, Fax servers included).

Pass-Through digitizes the fax tone, packages it into RTP and passes it over an IP network. Relay codes the fax tone into a transcribed message, relays the message to the other end and the other end regenerates the tone. T.38 is just like relay except that it is not proprietary like relay.

In your case, please get the data listed below so I may go through that information and suggest next steps.

- Get a detailed end-to-end calls flow. Include every element from the sending fax machine / server to the receiving fax machine / server. Trunk groups, Port Networks, Network Regions are all important.

- Get a screen capture of all the Network Regions and IP codec sets involved in the call.

- Get details of the sending fax machine / server and receiving fax machine / server. Make and model details are also important.

- What happens in a failed call? One or some pages transmits successfully / No page is transmitted / Distorted image etc.

Suresh R

Principal Engineer
Defects Diagnostics and Escalations
Avaya Global Services
Reply With Quote