Here is the topology,
Analog Phone <==> PABX <==>E1<==>VG<==>CM<==>IP Phone
Call from Analog phone to IP Phone is ok
Call from IP Phone to Analog is not ok
Cause code : 88
"Csim start" from VG to IP Phone is ok
"Csim start" from VG to Analog is not OK
Communication between VG and PABX with E1 interface
Show ISDN status already "multiple frame established"
Any idea for this issue.
For more detail I will attach the configuration of the VG.