ERROR[10771] chan_dahdi.c: PRI Span: 3 XXX Invalid Progress indicator value received: 09

Hello guys!
I’ve got 4 E1 in my Asterisk NOW 2.0.2. I use 2 Digium TE220B. E1 and E3 is connected to PSTN, E2 and E4 is connected to my internal PBX. All calls from my internal PBX flow through Asterisk to PSTN. From time to time I see this error in CLI. It happens, when someone calls from inside to outside. This is log:
[2012-10-04 13:58:47] VERBOSE[7172] app_dial.c: – DAHDI/i3/1111111-684 is proceeding passing it to DAHDI/i4/139-6e5
[2012-10-04 13:58:48] ERROR[10771] chan_dahdi.c: PRI Span: 3 XXX Invalid Progress indicator value received: 09
[2012-10-04 13:58:48] VERBOSE[7172] app_dial.c: – DAHDI/i3/1111111-684 is ringing

I’ve replaced the original number to 1111111. It’s interesting, that this ERROR doesn’t interrupt the call. Everything seems works fine! But what is it? I just want to investigate, what it can be. Unfortunatly, I haven’t found something in Google.

Please, help me with it.
Thank you!

Digium provide great support for their hardware. You might give them a call.

Your other PBX is not sending a valid progress report so it is just informing you of this. I see this alot and it has never caused a problem for me with other customers.

Thank you very much, Tony!
I’m calm now!