WS-X6608 and Fax relay

[annayuzhao]

Each port of the WS-x6608 is a voice or DSP port. What confused me is that some document describes that 6608 can be configured as a fax relay(versus fax passthrough). Understand that fax relay is only used in a case like 2 fax machines communicated via IP WAN. For example, Fax-FXS-GW-IP-GW-FXS-GW. I didn't see how 6608 fits here. (Btw I used 6608 in a CCM solution where 6608 are PRIs to PSTN). Can anybody give me an idea where I am wrong? Thanks

[dweiner]

Fax-FXS port-IP-6608-PSTN uses fax relay or passthrough from the FXS port to the PRI port.Any time the fax call has an IP leg, including between ports within a chassis, relay or passthrough comes into play.

[annayuzhao]

Can you explain under which circumstance that there will be IP leg involved? My experience is that 6608 only support MGCP, IP leg only involves when incoming call from PRI to IP Phones via CCM. I can't imagine when the ip leg will be used unless a ATA is attached on the network and a fax connects the ATA analog port. is this right? Thanks

[pbarman]

Right, you will have the fax connected to either a ATA, VG248 or a router FXS port. In all of these cases, there is a VoIP leg/link between the 6608 PRI and the devices mentioned above.

[annayuzhao]

ok, good. Here is my next question:

In the following scenario: fax-ata-network-6608-pri-pstn. Which way does the fax relay or fax passthrough happen? From PSTN to ata or the otherway? Thanks

[thisisshanky]

First of all, the ATA supports only Fax pass through. Fax relay is out of question..Fax passthrough mechanism is bidirectional...the basic essence of fax passthrough is that the gateway device does not detect the difference between a voice call versus a fax call.

[annayuzhao]

My understading is regardless fax passthrough or fax relay, the fax concept is fax-gw-ip-gw-fax. Fax passthrough or relay is between the IP peer. So now my question is in the case we have ATA or VG248, which fax mechnism we should use on the router side as bellow :fax-ATA(or VG248)-IP-GW-fax. Thanks