I tested SpanDSP as an internal extension, and it worked like a charm. Now I am trying to receive faxes from a toll-free nufone DID. I am running g.711uLaw in on this line, so no to cause too many problems. However I receive the following errors after the fax is finished receiving: so the fax comes in Executing RxFAX("IAX2[NuFone@198.22.67.70:4569]/5", "/root/testfax9.tif") in new stack then the errors channel.c:1654 ast_set_read_format: Unable to find a path from ULAW to UNKN app_rxfax.c:253 rxfax_exec: Unable to restore read format on 'IAX2[NuFone@198.22.67.70:4569]/5 channel.c:1621 ast_set_write_format: Unable to find a path from UNKN to ULAW app_rxfax.c:259 rxfax_exec: Unable to restore write format on 'IAX2[NuFone@198.22.67.70:4569]/5' I googled around and could not find anything pertaining to this problem.