problem in transferring a fax to the SPA2102 using v27ter at 4800 or 2400

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Nov 17th, 2009
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I have the below problem ,please see customer symptoms below

We are running inter-working trials on our T.38 Gateway system with three phone adapters including a Linksys SPA2102. This SPA2102 has been upgraded to the latest firmware (5.2.10) but we are having trouble transferring a fax to the SPA2102 using v27ter at 4800 or 2400.

The same test setup with the SPA2102 works with v17 and v29, and also works at v27ter when used with a Patton ATA or a Grandstream 'Handy Tone'.

Using Bladeware 1.01 to send to the SPA2102 at v27ter 4800 also produces the same failure.

As a fax receiver we are using Faxlab 4.5. This indicates that the TCF is not actually transferred to Faxlab from the SPA2102.

Attached is the faxlab log (cisco_v29_v27.fxc), the last two transfers in the log are for a v29 transfer and then a v27 transfer to the SPA2102, the the v27 one failed.

The SPA2102 syslog output for the v29 and v27 tests are in the file 'cisco_syslog_v29_v27.log' .

Also attached is a Wireshark packet capture this shows that the TCF is actually being sent to the SPA2102, but it only ever sends one NSF/CSI/DIS sequence.

The test setup uses a loop back server on from the Aculab T.38 Gateway ( to the SPA2102 (”

In the manual  I found that the fax machine a speed  should be between 7200 and 14400 and v27ter is not working in that range of speed ,I told that to the customer he told me that from the SP2102 t declares v27ter,v29 and v17 capabilities. I saw the packets and really there’s v27ter.

My question is SPA can work at 4800 or 2400 rates and is’t compatible with v27ter? I’m attached the logs from customer.

Thanks in advance

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Alberto Montilla Tue, 11/17/2009 - 03:35
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  • Cisco Employee,

Dear Sir;

These speeds are not supported, that's the issue of the failure when using T.38.


rpingar Fri, 11/20/2009 - 22:18
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if those speed are not supported why there isn't any fallback to g711 as expected?????

I found it very irritating, I am asking a good solution for this issue since Sipura, then Linksys now Cisco..........

Then what is the tecnicla explanation about not supporting these speeds?



Alberto Montilla Sat, 11/21/2009 - 06:53
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  • Cisco Employee,

Hi Rosario;

Will escalate to engineering and will let you know.


rpingar Thu, 11/26/2009 - 10:27
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still waiting about an answer.




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