Showing results for 
Search instead for 
Did you mean: 

Welcome to the Cisco Small Business Community

Have a question? Click on a topic board below to get started in the community.


SPA 8800 T38: SIP/2.0 488 Not Acceptable Here

Hello Guys,

i have a small issue,

when i try to make my SPA run with my 3CX PBX for inbound faxing i always have this issue after the reinvite to t38:

SIP/2.0 488 Not Acceptable Here


21.4.26 488 Not Acceptable Here

The response has the same meaning as 606 (Not Acceptable), but only applies to the specific resource

addressed by the Request-URI and the request may succeed elsewhere.

A message body containing a description of media capabilities MAY be present in the response, which is

formatted according to the Accept header field in the INVITE (or application/sdp if not present), the same

as a message body in a 200 (OK) response to an OPTIONS request.

What could it be?

I have read the Asterisk DOC for setup and fax and followed it acordingly.

The same fax server behind the SPA works fine with Patton, BeroNet, GrantStream but i have never seen this answer before.

What can i change. I have attached a Pcap.

Thx for any idea...


Frequent Contributor

Please attach the config of the unit.  Using IE, do a File/Save As and attach the html file. Make sure you are logged into the voice side as admin/advanced. Thanks.

Hello nesto,

here is the file.

The IPs are not more as in my test plz to ignore this due to it is reg. normaly to a different pbx.

Line one is where i made the changes...

Thx already!

Frequent Contributor

Config looks ok.  The fax rate coming in, what speed is that?  9600 is best.  Please send ethereal trace so we can see the transaction.

pcap is attaced to the first post, or dou you pref. a syslog from the box?

Frequent Contributor

Got it, I will confer with dev in looking at this 488 message.

Frequent Contributor

I've logged this as a bug. # CSCtf33838 in our db.

The 8800 is based on the 3102 and the 3102 shows in it's config, the options for FAX enable T38, FAX T38 Redundancy and FAX Tone Detect Mode.  I don't see these three parameters in the 8800 config.  This three parameters needs to be addressed for the next release version of spa8800.