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STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
PROPRIETARY AND CONFIDENTIAL
167
framing formats. A logic 1 in the ESF bit position selects ESF; a logic 0 bit
enables FMS1 and FMS0 to select SF, T1DM, or SLC96.
FMS1,FMS0:
The FMS1 and FMS0 bits select standard superframe, T1DM, or SLC96
framing formats. A logic 00 in these bits enable the SF framing format; a
logic 01 or 11 in these bit positions enable the T1DM framing format; a
logic 10 in these bit positions enable the SLC96 framing format. When ESF
is selected (ESF bit set to logic 1), the FMS1 and FMS0 bits select the data
rate and the source channel for the facility data link data. A logic 00 in these
bits enable the FRMR to receive FDL data at the full 4 kHz rate from every
odd frame. When ESF is selected, FMS1 and FMS0 settings other than
logic 00 are reserved and should not be used.
The valid combinations of the ESF, FMS1, and FMS0 bits are summarized in the
table below:
Table 31
- T1 Framing Modes
ESF
FMS1
FMS0
Mode
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Select SF framing format
Select T1DM framing format
Select SLC96 framing format
Select T1DM framing format
Select ESF framing format & 4 kHz FDL Data Rate
Reserved
Reserved
Reserved
JPN:
The JPN bit enables Japanese variations of the standard framing formats. If
the JPN bit is a logic 1 and the ESF format is selected (ESF bit is logic 1), the
T1-FRMR complies to TTC JT-G704. If the JPN bit is a logic 1 and a non-
ESF format is selected (ESF bit is logic 0), it is assumed the 12
th
F-bit of the
superframe carries a far end receive failure alarm. The alarm is extracted
and the framing is modified to be robust when the alarm is active.