[Asterisk-Users] Fax support and 'f' DTMF tone extension

[Diego Ercolani]

Hello,
probably is a feature what I'm asking for but because of my inexperience to asterisk this is my question:

I've configured CAPI ISDN to receive calls. When I receive a Fax call, I expected that asterisk understand it and then launch f (or fax) extension......
Infact, asterisk understand fax machine tone that classically modem shows as 'f'.

But 'f' isn't a real DTMF tone that are 0 to 9, a to d, * and # so correctly asterisk complain about this.
This causes asterisk not to signal at all the fax call to the dialplan.

Here it is a session viewed from the asterisk's console:

    -- SIP/gs2-eed0 is ringing
    -- SIP/gs2-eed0 answered CAPI[contr1/515387092]/8
Mar 10 14:30:33 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:30:33 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:30:37 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:30:38 WARNING[311316]: chan_sip.c:495 retrans_pkt: Maximum retries exceeded on call 66fd28a946cf6310464b890436521a47 at 192.168.1.5 for seqno 102 (Request)
Mar 10 14:30:38 WARNING[311316]: chan_sip.c:495 retrans_pkt: Maximum retries exceeded on call 66fd28a946cf6310464b890436521a47 at 192.168.1.5 for seqno 102 (Request)
Mar 10 14:30:40 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:30:44 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:30:47 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:30:51 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:30:54 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:30:58 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:31:01 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:31:05 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:31:08 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
Mar 10 14:31:11 WARNING[622614]: rtp.c:856 ast_rtp_senddigit: Don't know how to represent 'f'
 == Spawn extension (CAPI, diego, 1) exited non-zero on 'CAPI[contr1/51533792]/8'