Section 360-880-202
10
Secondary T1
Timeslot
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Figure 9. Timeslot Allocation with T1-S and ST1U
4.5
Timeslot Mode (Normal Mode Only)
The ST1U and T1-S use the timeslot mode to control the routing of data between T1-S and ST1U. The timeslot
mode can be set to idle or broadcast.
4.5.1. Timeslots Allocated on both Primary and Secondary T1 Circuits
When a timeslot from the primary T1 is allocated to a channel and the same timeslot on the secondary T1 is allo-
cated to another channel, the data is routed between the channels and the individual timeslot of the two T1s.
With this allocation the timeslot mode for both the primary and secondary T1s will be ignored. This allocation
mode is referred to as “Drop and Reinsert” because, the timeslot data is dropped and reinserted between one of
the T1s and the allocated channel. Data from a different channel is dropped and reinserted between the channel
and the same timeslot of the other T1.
Primary
Secondary
W
D/I
E
Time Slot Mode has No Effect on Data in Both Directions
Figure 10. Drop at T1 Primary and Secondary for the Same Timeslot
4.5.2. Timeslot Allocated on the Primary T1 Circuit
When a timeslot from the primary T1 circuit is allocated to a channel, the timeslot mode of the primary T1 circuit
will be ignored and not affect the routing of the data. If the timeslot on the secondary T1 circuit is set for idle,
then the output data for the timeslot on the secondary T1 circuit will be an all ones (11111111) which equates to an
“idle” signal. If the timeslot on the secondary T1 circuit is set for broadcast, then the output data for that timeslot
of the secondary T1 circuit will be the same data that is received from the timeslot on the primary T1 circuit. This
allocation is called “Broadcast mode” because the data from the time slot on the primary T1 circuit is broadcast to
both the channel and the secondary T1 timeslot.
Primary
Secondary
W
D/I
E
Controlled by Secondary T1 Time Slot Mode
Figure 11. Drop at T1 Primary with No Drop on Secondary
