Gsm  pabx telephone systems

                                                                      Main funcitons

One GSM card for a external line

External and internal caller ID

Busy transferred

Operator attendant

Auto attendant

Party Conference ( between 2exts & 1C.O ) 

Extension outgoing call class

Outside ( CO ) Line Duration Time Limit

Monitor voice record

Various Outside ( CO ) line access mode 

Extension number assignable freewill

Call picked up by non-ring extension

Call forwarded to assigned ext. ( when absent)