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STANDARD PRODUCT
PM8315 TEMUX
DATASHEET
PMC-1981125
ISSUE 7
HIGH DENSITY T1/E1 FRAMER WITH
INTEGRATED VT/TU MAPPER AND M13 MUX
PROPRIETARY AND CONFIDENTIAL
115
value (RDI, Remote Defect Indication) reflected in the V5 byte of the outgoing
tributrary path overhead. In Extended RDI mode, RDI indications are encoded
as a two bit value (RDI, Remote Defect Indication and RFI, Auxiliary Remote
Defect Indication), and are reflected in both the V5 byte and Z7 byte of the
outgoing tributary path overhead.
Specifically, the outgoing path overhead bits are mapped as follows:
Path
Overhead
bits
Non-extended RDI
(ERDI=0)
Extended RDI
(ERDI=1)
V5 bit 3
REI
REI
V5 bit 8
RDI
RDI
Z7 bit 5
0
RDI
Z7 bit 6
0
RFI
Z7 bit 7
0
NOT(RFI)
In all cases, the RDI-V state will be sent for a minimum of 10 multiframes before
changing, unless a higher priority alarm is required.
9.35 Transmit Tributary Mapper (TTMP)
The Transmit Tributary Mapper block bit asynchronously maps up to 28 T1 or 21
E1 streams into an STS-1 SPE, TUG3 in a STM-1/VC4 or STM-1/VC3 payload.
The TTMP compensates for any frequency differences between the incoming
individual serial bit rates and the available STS-1 or STM-1/VC3 payload
capacity. The asynchronous T1 mapping consists of 104 octets every 500 μs (2
KHz). The asynchronous E1 mapping consists of 140 octets every 500 μs (2
KHz). Refer to the RTDM block for a description of the asynchronous T1 and E1
mappings.
The tributary mapper is a time-sliced state machine which uses a payload buffer
as an elastic store. The T1 or E1 streams are read from the payload buffer, and
mapped into VT1.5 Payloads and VT2 Payloads using bit asynchronous
mapping only.
The Tributary Mapper compensates for phase and frequency offsets using bit
stuffing. A jitter-reducing control loop is used to monitor the Payload Buffer depth