running back to the phone company’s switch, there is a data link designed to send serial
packets that also run back to the phone company’s PBX. When Centrex callers call voice
mail (or call another voice-mail user that forwards to voice mail), Unity is provided with a
serial packet as the line rings on the voice board. The fact that the lines are coming from the
phone company is not all that interesting to Unity. In fact, Unity cannot tell the difference
between a PBX and the phone company. What is interesting is the numbering plan typically
used by Centrex in comparison to the numbering plan you w ...
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