DTMFF for fax server

[IPOFF]

i am working with fax server using analog port with DTMFF settings at extension caller id tab.

i found that fax server sometimes got wrong DTMF, some digits are missing. Doubt analog port is sending wrong digits or fax server detect error.

is there any way to monitor the dtmf between the analog port and fax server?

came across a tech guy told me to "tune" the ipo dtmf time (inter-digit time) to make it slower for fax server detection. wonder is there anyone know how to tune??

thanks a lot