STANDARD PRODUCT
DATASHEET
PMC-1981125
ISSUE 7
PM8315 TEMUX
HIGH DENSITY T1/E1 FRAMER WITH
INTEGRATED VT/TU MAPPER AND M13 MUX
12.10 Telecom Bus Mapper/Demapper Loopback Modes
The TEMUX provides two loopbacks at the telecom bus interface to aid in
network and system diagnostics at the SONET/SDH interface. These loopback
modes can be enabled via the microprocessor whenever the SONET/SDH block
is enabled as the mapper for the T1/E1 framer slices or as the mapper for the
DS3 framer or M13 Multiplexer.
Telecom Diagnostic Loopback
The Telecom Bus Diagnostic Loopback allows the transmitted telecom bus
stream to be looped back into the receive SONET/SDH receive path, overriding
the data stream received on the telecom drop bus inputs. While Telecom
diagnostic loopback is active, valid SONET/SDH data continues to be
transmitted on the telecom add bus outputs. The entire telecom drop bus is
overwritten by the diagnostic loopback even though only one STS-1 SPE, STM-
1/VC4 TUG3 or STM-1/VC3 is generated by the egress VTPP onto the telecom
add bus. This loopback is only available for VT1.5/VT2/TU11/TU12 mapped
tributaries. DS3 mapped tributaries must use the DS3 diagnostic loopback. The
telecom bus diagnostic loopback mode is shown diagrammatically in Figure 45.
Figure 45
- Telecom Diagnostic Loopback Diagram
VTPP
VT/TU
Payload
Processor
RTDM
Receive
Tributary
Demapper
LDDATA[7:0]
LDDP
LDPL
LDC1J1
LADATA[7:0]
LADP
LAPL
LAC1J1V1
LAC1
VTPP
VT/TU
Payload
Processor
Telecom Line Loopback
The Telecom Bus Line Loopback allows the received telecom drop bus data to
be looped back out the telecom add bus after being processed by both the
ingress and egress VTPPs. Both VTPP must be setup for the same STS-1 SPE,
PROPRIETARY AND CONFIDENTIAL
210
PMC [ PMC-SIERRA, INC ]
