Section 360-880-202
11
4.5.3. Timeslot Allocated on the Secondary T1 Circuit
When a timeslot is allocated from the secondary T1 to a channel, the timeslot mode of the secondary T1 timeslot
is ignored and does not affect the data routing. Data is routed from the allocated channel to and from the time
slot on the secondary T1 circuit. If the timeslot on the primary T1 is set to idle, the output data for the timeslot on
the primary T1 will be an all ones (11111111) which equates to an “idle” signal. If the time slot on the primary T1 is
set to broadcast, then the output data on the primary T1 for the timeslot will be the same data that is sent from
the secondary T1 to the allocated channel. This allocation is called Broadcast mode because, the data from the
timeslot on the secondary T1 circuit is broadcast to the channel and to the primary T1 timeslot.
Primary
Secondary
W
D/I
E
Controlled by Primary T1 Time Slot Mode
Figure 12. Drop at T1 Secondary with No Drop on Primary
4.5.4. Non-Allocated Timeslots
When a timeslot is not allocated to either the primary T1 circuit or the secondary T1 circuit, the primary and sec-
ondary timeslot mode determines the data output on the respective T1. If the mode is set to idle, the output of the
timeslot will be an all ones (11111111) which equates to an “idle” signal. If the mode is set to broadcast then the
output of the timeslot on the T1 will be the data from the corresponding time slot on the other T1. This allocation
mode is referred to as “Pass Through” because, when both primary and secondary timeslot modes are set to
broadcast the data passes through the 360-80.
Primary
Secondary
W
D/I
E
Controlled by Secondary TS Mode
Controlled by Primary TS Mode
Figure 13. No Drop at T1 Primary or Secondary
4.6
Forced Bypass (Manually Selected via Management Normal Mode Only)
If this option is selected for an ICB, it will require local intervention at the site of the ICB to reset.
Restoring normal error free operation of the ICB will require a “reset” to return to stored values on a
local craft interface or Ethernet connection, or removing both the T1-S and ST1U. The cards must
then be reinserted in order, first the T1-S, followed by the ST1U.
WARNING
Card configuration is stored in an EEPROM so no additional settings adjustments are required.
4.7
Facility Alarm Handling
The alarm timing circuit provides the indications and timing for the trunk processing. Hit integration for Frame
Loss (FRL) is provided to prevent trunk processing during intermittent frame losses. LEDs are provided for local
red alarm (AR) and remote yellow alarm (AY).
The T1-S provides three optional trunk processing timing options (both primary and secondary T1s are configured
the same) that are selected via the NMS software. In the NORMAL position, the unit provides standard D4 timing.
In the CM2 & CM3 positions, special shortened timings are provided.
When a loss of signal or framing is detected on the WEST receive facility, a Red Alarm (AR) is declared and the
WEST AR LED is illuminated after 2.5 seconds (1 second if CM2 option is selected or immediately if the CM3
option is selected), and the unit will begin its trunk processing routine. This causes the following:
