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Jack_son_ asked
Medium Priority
Last Modified: 2012-05-06
To send a fax thru an ata, does the image have to be SIP vs SCCP?  I have dial tone but faxing does not work.
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It depends on your voip service. Some support faxes while others don't.


Its using Cisco call manager

Your codec for that line needs to be G711 or T.38.

G711 will work on short low jitter hops. Ie. Local network.
If you attempt to use it over a WAN link it will most likely not work.

T.38 is the ratified Fax over IP protocol. You should use this whenever you can.


For some reason this stilll wont fax; are there any other ways to get fax running thru Call Manager?

Are you using T.38?
What type of ATA are you using?
I have seen issues in the past with certain ATAs not being able to send faxes.


ATA186, has SCCp image.  
I am new to the Fax over VOIP concept, so I guess I need to check the GW for this protocol and the fax machine?  

Fax machine does not need to be anything special.
If the ATA and Gateway both support T.38 use that.
The ATA186 is just the station side of the connection, you also need to consider the path going to the Voice gateway connected to the PSTN.  What are you using for signalling from the Callmanager to the VG?  H.323, MGCP or SIP?   Also, is the ATA-186 configured in the same location as the voice gateway?  Same Region?  What codec is specified for the region?

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