Toshiba Strata CTX100, Installation And Maintenance Manual

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T1
Hardware and Cabling
6-8
Strata CTX I&M 10/02
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Red Alarm (FALM and MFALM)—When FALM and MFALM are both On steady, a Red
alarm condition exists. This indicates that the RDTU does not detect a proper carrier signal
(1.544 mbs T1) on its receive pair and the RDTU is not synchronized. When the Red alarm
condition exists, the RDTU should turn the BSY LED On steady and attempt to send a Yellow
alarm signal (RDTU YALM LED flashes) to the far end T1 circuit.
•
Yellow Alarm (YALM)—When the far end network or CPE T1 does not detect the RDTU
transmitted 1.544 mbs T1 carrier signal on its receive pair the far end T1 sends a Yellow alarm
signal pattern to the RDTU—the RDTU should turn on the YALM LED (the YALM repeats the
signal it receives from the far end—flashing or steady). If the RDTU does not receive the far
end carrier signal, the RDTU sends the Yellow alarm signal to the far end and causes the BSY
and YALM LEDs to flash.
•
Blue Alarm (BALM)—The Blue alarm, also known as the Alarm Indication Signal (AIS), is
detected by the RDTU. This signal is sent by the Far End Network equipment to RDTU when it
loses the carrier from a Network T1 circuit (other than RDTU). This signal assures that the
RDTU maintains synchronization when there is a problem between two Network Nodes. The
RDTU BALM also lights if the far end sends a Blue alarm signal during loop back. The RDTU
sends a Blue alarm signal when loop-back test is being performed.
Synchronization LEDs
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Primary Synchronization (PSYNC) LED (see Figure 6-1 on page 6-3 ) – If one RDTU PCB is
assigned as the Primary Timing T1 PCB in Program 105, the PSYNC LED of this RDTU PCB
flashes when it is synchronized with the far end T1 span line clock provider. If the Primary
RDTU is not synchronized with the clock provider, the PSYNC LED will be On steady. The
SSYNC LED of the Primary sync RDTU PCB should always be Off. The Primary sync RDTU
PCB synchronizes the RTCU (time-switch) to the clock signal it receives from the T1 span
circuit to which it is connected. The RTCU then synchronizes the Strata CTX PCM talk path
(time-switch) to the far end PCM talk path.
•
Secondary Synchronization (SSYNC) LED – If an RDTU PCB is assigned as the Secondary
time T1 PCB in Program 105, its SSYNC LED will be On steady (standby mode) when the
Strata CTX is synchronized to the Primary T1 clock provider. In the event of a loss of Primary
synchronization (when 4 out of 12 consecutive frame timing bits are in error) the Strata CTX
switches from synchronizing to the Primary RDTU span line clock to the span line clock
connected RDTU designated as the Secondary Timing Reference. When the Strata CTX is
synchronized to the Secondary Reference RDTU, the PSYNC LED on the Primary Reference
RDTU turns on steady and the SSYNC LED on the Secondary Reference RDTU will flash.
•
Run Free (PSYNC/SSYNC) – If the RDTU PCB is the clock provider to the Far-end T1 span
circuit both the PSYNC and SSYNC LEDs are always Off.
RDTU Cable Installation
The RDTU PCB is shipped with a Toshiba NDTU cable for connecting the RDTU PCB to a CSU.
The NDTU is a 30 ft. cable and is specially made to conform with EIA specifications (see
Figure
6-7 ).
All other cables required to connect the T1 span line to the RDTU PCB are customer-supplied and
must conform with EIA specification, see the Notes of
Figure 6-7 . Almost all CSU manufacturers
supply cables that comply with T1 span specifications for connecting the CSU to customer
premise equipment (like Strata CTX, RDTU) to the Network Interface equipment.