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Cisco SPA112 Adapter

Just changed router to a BT business hub5 and therefore needed to use SPA 112 adapter to use a voip telephone line for a brother all in one fax machine. The fax machine can dial out and send faxes but cannot receive. Does anyone know what adjustments need to be made on the cisco adapter, fax machine or router?

Thanks

6 REPLIES
VIP Purple

Is it at least ringing?

Is it at least ringing?

If it is, then it is probably a CODEC issue.  These are the settings we use.  We use G711A in our country, yours might use G711U.  However the important bit is the T38 support.

<FAX_Enable_T38_1_ ua="na">Yes</FAX_Enable_T38_1_>
<FAX_Disable_ECAN_1_ ua="na">Yes</FAX_Disable_ECAN_1_>
<FAX_Passthru_Codec_1_ ua="na">G711a</FAX_Passthru_Codec_1_>
<Network_Jitter_Level_1_ ua="na">low</Network_Jitter_Level_1_>
<Jitter_Buffer_Adjustment_1_ ua="na">No</Jitter_Buffer_Adjustment_1_>

Hi Philip,

Hi Philip,

Thanks for your response. It does ring and makes the normal fax noise but no fax!

I'll try your suggestions.

Thanks

VIP Purple

This sounds exactly like the

This sounds exactly like the issue that the above config will resolve.  Did it help?

Hi,

Hi,

Changed the T38, ECAN 1 and Passthru _ Codec 1 but Network Jitter and Jitter Buffer were not options om my SPA112.

Fax machine rings says it is receiving but nothing comes through.

Thanks.

VIP Purple

It is essential those two are

It is essential those two are changed for fax to work (doesn't work for us if we don't change those).  Perhaps try changing them in the GUI.  They are likely to be an advanced option.

I am also assuming the fax is plugged into port 1 (otherwise change everything to _2).

New Member

One thing you may have to do

One thing you may have to do to receive faxes is lower the baud rate/speed in the fax settings and/or disable ECM (Error Correction Mode). 

A lot of newer faxes are set to send/receive at 33.6k, but that speed generally will tend to fail over VOIP. It's generally recommended to lower it to 14.4k or lower. I set mine to 9600. And ECM will cause faxes to fail if too many packets drop, so you can see why that might be problematic. Here's a reference - 

http://www.voipmechanic.com/voip-fax-settings-9600-baud.htm

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