I hope I answered all the questions. Also, the time slipping is happening to other PBX in one of our building from the same T1 carrier. The PBX is manufactured by Toshiba. This PBX is not the one I mentioned about these 2 PBX (Master & Slave). It is completely a different PBX box. The same error happening on this PBX. Since the Toshiba PBX is not linked to T1-PRI, just a T1 analog, the problem is not recognized by users.
