Re: [hylafax-users] Failure to receive silence (synchronization failure)

["Alex R [MaxoTel]" <alex@xxxxxxxxxxx>]

Lee,
Thanks for your fast response!

The VoIP server that this is on is very close to the terminations, so it
shouldn't have anything to do with the quality or delay of the VoIP call,
plus I can get an identical result every time I do it (unless the VoIP call
to certain numbers is handled differently at the provider)

A friend of mine said he had to adjust the tx/rx volume on his VoIP switch,
but I'm using Asterisk. Could that be the problem?

Regards,

Alex R.


-----Original Message-----
From: Lee Howard [mailto:faxguy@xxxxxxxxxxxxxxxx] 
Sent: Tuesday, 15 April 2008 10:50 PM
To: Alex R [MaxoTel]
Cc: hylafax-users@xxxxxxxxxxx
Subject: Re: [hylafax-users] Failure to receive silence (synchronization
failure)

Alex R [MaxoTel] wrote:
>
> Took me a while to figure out how to subscribe to this mailing list! 
> Why doesn't Hylafax have a regular web forum?
>

You mean, like this? :

http://sourceforge.net/forum/?group_id=148904

> My problem:
>
> Someone has recently set up Hylafax for me, and confirmed it working 
> with my canon fax machine.
>
> Hylafax is connected to Iaxmodem, which is connected to asterisk, 
> which sends the fax using SIP to the provider in the same datacenter 
> (for good results).
>
> When sending a fax to my canon fax machine, it works 100% of the time. 
> Picture perfect - I must have sent 15 faxes to it while testing. But 
> when I am sending to some other destinations it fails exactly the same 
> way each time.
>
> Here are the log files:
>
> http://119.63.202.100/canon.txt <- works
>
> http://119.63.202.100/fail.txt <-fails
>
> It seems to me like hylafax doesn't know how to talk to this other fax.
>

It's almost undoubtedly a VoIP problem... nothing to do with HylaFAX.

Apr 15 15:37:14.09: [ 3314]: <-- [7:ATDT38\r]
Apr 15 15:37:28.11: [ 3314]: --> [7:CONNECT]

HylaFAX tells IAXmodem to dial, and the modem does and it detects a fax
answer on the receiver.

Apr 15 15:37:38.11: [ 3314]: <-- data [1]
Apr 15 15:37:38.12: [ 3314]: --> [2:]
Apr 15 15:37:38.12: [ 3314]: --> [2:OK]

However, after 10 seconds of demodulation no HDLC frame data is received.
So HylaFAX aborted the command.  Now it's going to wait for silence...

Apr 15 15:37:38.12: [ 3314]: <-- [9:AT+FRS=7\r]
Apr 15 15:38:08.12: [ 3314]: MODEM <Timeout>
Apr 15 15:38:08.12: [ 3314]: Failure to receive silence (synchronization
failure).
Apr 15 15:38:08.12: [ 3314]: <-- data [1]
Apr 15 15:38:08.13: [ 3314]: --> [2:OK]

But after 30 seconds waiting for silence there never is any, and so HylaFAX
aborts that, too.  Now it's going to try to listen for V.21 HDLC
signaling...

Apr 15 15:38:08.13: [ 3314]: <-- [9:AT+FRH=3\r]
Apr 15 15:38:10.70: [ 3314]: --> [4:BUSY]

But it gets a "BUSY" response from IAXmodem (I've never seen *that* before).
But basically the call is lost by now.  The receiver has hung up.

Apr 15 15:38:15.13: [ 3314]: --> [0:]
Apr 15 15:38:15.13: [ 3314]: MODEM <Empty line>
Apr 15 15:38:15.13: [ 3314]: <-- data [1]
Apr 15 15:38:15.33: [ 3314]: MODEM <Timeout>

IAXmodem doesn't handle the BUSY after AT+FRH=3 properly.

Apr 15 15:38:15.33: [ 3314]: No receiver protocol (T.30 T1 timeout)
Apr 15 15:38:15.33: [ 3314]: SEND FAILED: JOB 61 DEST 38 ERR [126] No
receiver protocol (T.30 T1 timeout)
Apr 15 15:38:15.33: [ 3314]: <-- [9:AT+FRS=7\r]
Apr 15 15:38:15.33: [ 3314]: --> [5:ERROR]

The modem is on-hook, and thus the ERROR result here.

Apr 15 15:38:15.33: [ 3314]: MODEM Command error
Apr 15 15:38:15.33: [ 3314]: Failure to receive silence (synchronization
failure).
Apr 15 15:38:15.33: [ 3314]: <-- [9:AT+FTH=3\r]
Apr 15 15:38:15.33: [ 3314]: --> [5:ERROR]

Again, the modem is on hook, so thus ERROR.

Apr 15 15:38:15.33: [ 3314]: SEND FAILED: JOB 61 DEST 38 ERR [333] No
receiver protocol (T.30 T1 timeout); too many attempts to dial
Apr 15 15:38:16.34: [ 3314]: <-- [5:ATH0\r]
Apr 15 15:38:16.44: [ 3314]: --> [2:OK]

And now HylaFAX gets the picture that the session is done and so it, too,
"hangs up" (although the modem is already on hook).

Thanks,

Lee.



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