XRT94L33_1 Datasheet, PDF (57/110 Pages) Exar Corporation – 3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER ATM/PPP - HARWARE MANUAL

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XRT94L33
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AF15 STS1TXA_ALARM_2 I
RXDS3NEG_2
RxLCV_2
TTL
Transmit STS-1 Telecom Bus – Alarm Indicator
Input/Receive DS3/E3 Negative-Polarity Data Input from
LIU/Receive DS3/E3 Line Code Violation Input from LIU –
Channel 2:
The exact function of this pin depends upon whether the STS-
1 Telecom Bus Interface for Channel 2 has been enabled or
not.
If STS-1 Telecom Bus (Channel 2) has been enabled –
STS-1 Transmit Telecom Bus – Alarm Indicator Input:
This input pin pulses “high” coincident to any STS-1 signal
(which is carrying the AIS-P indicator) being applied to the
STS1TXA_D_2[7:0] input data bus.
Note:
If the STS1TXA_ALARM_2 input signal pulses
“HIGH” for any given STS-1 signal (within the
“incoming” STS-1), then the XRT94L33 will
automatically declare the AIS-P defect condition for
that particular STS-1 channel.
If STS-1 Telecom Bus (Channel 2) has NOT been enabled:
If the STS-1 Telecom Bus (Channel 2) has NOT been
enabled, then the role that this particular input pin plays
depends upon whether Channel 2 is operating in the STS-1
Mode, the DS3/E3 Single-Rail Mode or in the DS3/E3 Dual-
Rail Mode, as described below.
If Channel 2 is operating in the STS-1 Mode
If Channel 2 is operating in the STS-1 Mode, then the user
should tie this pin to GND.
If Channel 2 is operating in the DS3/E3 Single-Rail Mode –
Receive LCV Input from LIU
If Channel 2 is operating in both the DS3/E3 and Single-Rail
Modes, then this input pin will function as the LCV (Line Code
Violation) input. In this mode, the user is expected to connect
the “LCV” output pin from the LIU IC to this input pin. The
DS3/E3 Framer block will sample this input pin upon the “user-
configured” edge of the “RXDS3LINECLK_2” clock signal, and
the Primary Frame Synchronizer block (corresponding with
Channel 1) will increment the PMON LCV or EXZ Event Count
registers based upon the data sampled at this input pin.
If Channel 2 is operating in the DS3/E3 Dual-Rail Mode –
Receive DS3/E3 Negative-Polarity Data Input from LIU
If the user has configured Channel 2 to operate in both the
DS3/E3 and the Dual-Rail Mode, then only the “negative-
polarity” portion of the Receive DS3/E3 data should be applied
to this input pin.
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