Sorry for the delayed response.
Just seen this this thread.
For ISUP you generally have the following messages exchanged before
you can use a CIC for TX. IAM, SAM, ACM, CPG, ANM, etc..
IAM has the digits, BCIE, HLC, LLC, etc.. ACM confirms that the information has
been received and the node is ready to process the request.
ANM (ANS) is the message that initiates charging and is the “trigger”
for the switch to start the process to generate a Call Record based on
the call duration.
TMR will be used to see if Speech, 3.1KHz audio, 64K unrestricted (or N*64), etc.. is
required.
For your case you have a node that has mapped ss7/ISUP. to analog and it has been mapped back
to ss7/ISUP. Careful attention must be made with the mapping of ISUP to your legacy analog signalling
system.
Let me know if you need any more support.
VBR/ Wallis Dudhnath