If you have the newer software in the system you can log into it using procomm and the RS232 port on the cabinet. Then you can get to the programming. I will have to dig out my medley manual and can scan the programming information. Send Private email and include your email address and I will get it together for you if you cannot log into system and figure it out that way.
Can't remember if there is something to adjust DTMF


mjc