Specifications

Page 20–8
FOCUS System Manual
For instructions on configuring the Addressable
Two-Wire Voice Module, please refer to the FCS
online help facility (Configuring the FOCUS
Channel Modules ↓ Addressable Two-Wire Voice
Module (PBW/PBT)…).
The default address for the module is the last three
digits of the terminal ID of the chassis in which
the module is installed. If this is the desired phone
number, you can skip the configuration setting and
proceed with mapping the module’s DS0 time
slots.
20.3.3 DS0 Time Slot Assignment
After installing and connecting the hardware and
assigning the module’s phone number, the next
step is to map, or assign, the DS0 time slots for the
module. You assign one time slot for each
direction (i.e., each transceiver stream).
If you are setting up an entire network, we
recommend that you map the time slots for each
module as you install it.
We also recommend that, before making the
actual time slot assignments via the FCS, you first
write or sketch out the assignments for the entire
network.
An example of DS0 time slot mapping for a
network configured in a loop is shown in Figure
20-6. Beginning with the first chassis in the loop
(Station A in this example), each chassis’ voice
channel “a” is mapped to the next chassis’ voice
channel “b,” using the same, or different time slot
(time slot 5 in the example). Also, to prevent idle
noise on the network line, voice channel “b” on
the first chassis (Station A) and voice channel “a”
at the last chassis (Station D) are each mapped to
an unused time slot on the other.
X1-2
Time
Slot
3
AB
Station A
PBW/PBT
Voice Channels Voice Channels
Unused
Time
Slots
AB
Station B
PBW/PBT
X1-1
Time
Slot
3
X1-1
Time
Slot
24
X1-2
Time
Slot
2
AB
Station D
PBW/PBT
Voice Channels
X1-1
Time
Slot
4
X1-2
Time
Slot
5
AB
Station C
PBW/PBT
Voice Channels
X1-1
Time
Slot
5
X1-2
Time
Slot
4
Figure 20–6. Sample Time Slot Mapping for a PBW/PBT Network within a FOCUS Loop Configuration.