I created this small patch for chan_ss7 to make it support all available HEX signs. The digits 0 to 9 and the characters B, C and E were already supported. Ok F as well but this indicates the end of the dial process.

diff chan_ss7-0.10.1/l4isup.c chan_ss7-0.10.1-mcs/l4isup.c
1464a1465,1468
> //patch support for all HEX
> else if ((number[i] == ‘a’) || (number[i] == ‘A’))
> d = 0×0a;
> //end
1468a1473,1476
> //patch support for all HEX
> else if ((number[i] == ‘d’) || (number[i] == ‘D’))
> d = 0×0d;
> //end