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New Member

Fax over IP CODEC G723.1 5.3K

Hi,

I have problem setting up Fax Over IP on AS5300. I have used CODEC G723.1 with 40 byte. Voice is working fine. Fax drop almost immediately.

4 REPLIES
New Member

Re: Fax over IP CODEC G723.1 5.3K

CODECs are designed from samplings of human voices and are designed to simulate the closest matching voice patterns. They don't work properly with faxes for this reason. You must use straight G711 for faxes to work.

New Member

Re: Fax over IP CODEC G723.1 5.3K

Hi,

I think FAX will work fine with G711 only, I never tried it with other CODEC but I think it will not work.

New Member

Re: Fax over IP CODEC G723.1 5.3K

Hi,

I had also the same problem with G.723 codecs,now I use G.729 codec - it works fine for fax.

New Member

Re: Fax over IP CODEC G723.1 5.3K

In my experience g.729 is not very well suited for fax. That said, I have had faxes complete with g.729. One option is the the AS5300 can support fax-passthrough (depending on IOS). With fax pass-through the 5300 detects the fax gaurd tone and will then just pass it through using G.711 for the call.

Hope this helps.

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