Important Pri Channel Information - Polycom ViewStation EX Api Manual

API Guide for ViewStation EX, ViewStation FX, and VS4000
246
Note This screen is only accessible if you have a PRI network interface
connected to your system.

Important PRI Channel Information

Outgoing Call. For an outgoing call, the ViewStation FX or VS4000 system
uses the first active and available channel starting with the lowest number
from the channel range (1-23 for a PRI T1 and 1-30 for a PRI E1). If an
additional channel is needed, the system chooses the next incremental
number. For example, if channels 1 through 7 are inactive, but 8 is active and
available, then 8 is the first channel that can be used by the ViewStation
ViewStation FX or VS4000 system to place an outgoing call. If an additional
channel is needed, the system will use the next available active channel in the
range (which could be 9, and so on).
Incoming Calls. For incoming calls, the ViewStation FX or VS4000 system
may use the highest numbered channel in the range and, if needed, proceed
to the next channel number in descending order, depending on the type of
third-party equipment attached to the system. For example, an incoming call
arrives on channel 23, then 22, 21, and so on.
Dedicated full PRI T1 or E1 Line. All channels should be active for a full T1 or
E1 line dedicated to your ViewStation FX or VS4000 system.
Fractional PRI T1 or E1. Channel selection should be handled by your PRI
network administrator.
PRI E1 Channel Information. The PRI Status screen (for E1) shows 30
channels. However, E1 trunk lines have 32 timeslots, numbered 0 - 31.
Timeslot 0 is used for framing, and timeslot 16 is used for call signaling (the
D channel). The remaining 30 timeslots are used as bearer (data) channels. In
call signaling between our equipment and the switch, these channels are
numbered 1-15, 17-31. But the PRI Status screen numbers these channels
contiguously in the range 1-30. Therefore, on the PRI Status screen, channels
1-15 control the status of timeslots 1-15, and channels 16-30 control the status
of timeslots 17-31.
www.polycom.com/videodocumentation