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Super G3/G4 Fax

Is it possible to get Super G3 or Super G4 faxing to work over CUCM/VoIP ?

GTG

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7 REPLIES
VIP Super Bronze

Super G3/G4 Fax

Gordon,

Cisco IOS gateways with Cisco IOS Release 12.4.4T and later offer support for Super Group 3 (SG3) fax transmissions when T.38 or Cisco fax relay are configured; however, only Group 3 speeds are negotiated.

If it is necessary to transport SG3 high-speed faxes at their native speeds, then modem passthrough must be used. With the release of Cisco IOS version 15.1.1T, a new feature will provide native support for SG3 faxes by T.38 fax relay.

See detailed asnwer here.. I dont think Super G4 is supported though. Cant see any reference to it.

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/8x/gateways.html#wp1064689

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"There is a wideness in God's mercy Like the wideness of the sea.There's a kindness in His justice Which is more than liberty"

Please rate all useful posts "The essence of christianity is not the enthronement but the obliteration of self --William Barclay"
Super Bronze

Super G3/G4 Fax

Hi

If you are talking ATAs - then definately not. Expect v.slow fax... like 9600k.

IOS based gateways have lots of features (in t.38 mode) aimed at preventing faxes from negotiating complex connections, forcing them to negotiate G3 rather than Super G3, disabling ECM etc. so although you will get better performance from a properly configured IOS gateway over an ATA, I would always set expections quite low.

If speed is really important it's probably best to look at a proper server fax solution rather than hoping to push the performance of a fax machine over IP.

It'll save some trees as well :-)

Aaron

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

Super G3/G4 Fax

One of the problems I'm getting, is that many standard fax machines try and use Super G3/G4 and won't reliably down-speed to 14.4 Kb/s. This isn't with just cheap fax machines, but also higher cost/spec fax machines too.

GTG

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Super G3/G4 Fax

On my CUCM setup, I can't get close to 33.3 Kb/s speed with modem pass-through.

We're trying to play with T.38 at the moment, but, that's giving speeds worse than modem/fax pass-thru !

GTG

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VIP Super Bronze

Re: Super G3/G4 Fax

What IOS are you on?  are you using VG 224, 204, 202? ?Please note that modem passthrough and modem-passthrough are not the same. Try modem passthrough wihtout the  hyphen

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"There is a wideness in God's mercy Like the wideness of the sea.There's a kindness in His justice Which is more than liberty"

Please rate all useful posts "The essence of christianity is not the enthronement but the obliteration of self --William Barclay"

Super G3/G4 Fax

I'm trying with the latest IOS (15.2-3.T1)

What's the difference between the two modem passthrough commands ?

GTG

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VIP Super Bronze

Super G3/G4 Fax

one is configured with modem pass-through, the other is configured with modem passthrough(this is the one you shuld try)

Please rate all useful posts

"There is a wideness in God's mercy Like the wideness of the sea.There's a kindness in His justice Which is more than liberty"

Please rate all useful posts "The essence of christianity is not the enthronement but the obliteration of self --William Barclay"
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