Thank you for responding.
While I am very new to FreePBX and Asterisk I started working on T1’s in the late 70’s. I was Voitek / Datek with Telco before deregulation and thus changing careers.
A T1 is a synchronous service. In it basic form lets say 2 channel banks talking to each other one will provide the clock, and the other must lock to that clock.
I have seen many different ways of describing this relationship. Master / slave, Internal / loop and many others. Sorry if I was not using the current terminology.
Now with respect to a switch, they must also be in time with each other else the results are frame slips.
the Class 1 C.O. was the master clock and moving down to the Class 5 C.O. (the local co) was receiving the Class 1 clock via the Class 2,3,4 C.O…
Thus all C.O.'s where in time with each other.
Then the PBX in this case FreePBX (Asterisk) must be loop clocked to the TELCO.
The only setting available in the FreePBX GUI was for the Asterisk to generate it’s own clock. This causes frame slips.
I did figure out that in the /etc/dahdi/system.conf
span=1,0,0,ESF,B8ZS = internal clock
span=1,1,0,ESF,B8ZS = loop clock
There is only one choice in the GUI, internal clock.
I edited the /etc/dahdi/system.conf as a test and it does resolve the problem, however the instructions say not to edit that file, and it refers me to a web page.
Unfortunately it did not cover (or I missed it)how to properly make a manual edit that will keep the system happy.
Hopefully this bug can be fixed, but it will probably take a long time.
until then I need guidance on how to correctly make this change.
Any help greatly appreciated.