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Advance Data Sheet
May 1998
T7633 Dual T1/E1 3.3 V Short-Haul Terminator
29
Lucent Technologies Inc.
Line Interface Unit: Receive
(continued)
Receive Line Interface Configuration Modes
(continued)
Loss Shutdown (LOSSD) and Receiver AIS (RCVAIS).
The loss shutdown (LOSSD) control bit (register
LIU_REG3, bit 4) acts in conjunction with the receive alarm indication select (RCVAIS) control bit (register
LIU_REG4, bit 1) to place the digital RLIU signals (RPD-LIU, RND-LIU, RLCK-LIU) in a predetermined state when
a digital loss of signal (DLOS) or analog loss of signal (ALOS) alarm occurs.
If LOSSD = 0 and RCVAIS = 0, the RND-LIU, RPD-LIU, and RLCK-LIU signals will be unaffected by the DLOS
alarm condition. However, when an ALOS alarm condition is indicated in the LIU alarm status register (register
LIU_REG0, bit 0), the RPD-LIU and RND-LIU signals are forced to 0 state and the RLCK-LIU free runs (at the
INTSYSCK/16 frequency).
If LOSSD = 1, RCVAIS = 0, and a DLOS alarm condition is indicated in the LIU alarm status register (register
LIU_REG0, bit 1) or an ALOS alarm condition is indicated, the RPD-LIU and RND-LIU signals are forced to the
0 state and the RLCK-LIU free runs (at the INTSYSCK/16 frequency).
If LOSSD = 0, RCVAIS = 1, and a DLOS or an ALOS alarm condition is indicated in the LIU alarm status register
(register LIU_REG0, bits 0 or 1), the RPD-LIU and RND-LIU signals will present an alarm indication signal (AIS, all
ones) based on the free-running INTSYSCK/16 frequency.
If LOSSD = 1, RCVAIS = 1, and a DLOS or an ALOS alarm condition is indicated in LIU alarm status register (reg-
ister LIU_REG0, bits 0 or 1), the RPD-LIU and RND-LIU signals are forced to 0 state and the RLCK-LIU free runs
at the INTSYSCK/16 frequency.
The RND-LIU, RPD-LIU, and RLCK-LIU signals will be remain unaffected if any loopback (FLLOOP, RLOOP,
DLLOOP) is activated independent of LOSSD and RCVAIS settings.
The default reset state is LOSSD = 0 and RCVAIS = 0.
The LOSSD and RCVAIS behavior is summarized in Table 3.
LIU Receiver Bipolar Violation (BPV) Alarm.
The receiver LIU bipolar violation (BPV) alarm is used only in the
single-rail mode. When B8ZS(DS1)/HDB3(E1) coding is not used (i.e., CODE = 0), any violations in the receive
data (such as two or more consecutive 1s on a rail) are indicated on the RND-LIU output. When B8ZS(DS1)/
HDB3(E1) coding is used (i.e., CODE = 1), the HDB3/B8ZS code violations, including BPVs, are reflected on the
RND-LIU output.
Table 3. LOSSD and RCVAIS Control Configurations (Not Valid During Loopback Modes)
LOSSD
RCVAIS
ALARM
RPD/RND
RLCK
0
0
ALOS
0
Free Runs
0
0
DLOS
Normal Data
Recovered Clock
1
0
ALOS
0
Free Runs
1
0
DLOS
0
Free Runs
0
1
ALOS
AIS (all ones)
Free Runs
0
1
DLOS
AIS (all ones)
Free Runs
1
1
ALOS
0
Free Runs
1
1
DLOS
0
Free Runs