DS21FT44/DS21FF44
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SYMBOL
POSITION
NAME AND DESCRIPTION
RFE
CCR2.0
Receive Freeze Enable. See Section 14 for details.
0=no freezing of receive signaling data will occur
1=allow freezing of receive signaling data at RSIG (and RSER
if CCR3.3=1).
AUTOMATIC ALARM GENERATION
The DS21Q44 can be programmed to automatically transmit AIS or Remote Alarm. When automatic
AIS generation is enabled (CCR2.5 = 1), the framer monitors the receive side to determine if any of the
following conditions are present: loss of receive frame synchronization, AIS alarm (all one’s) reception,
or loss of receive carrier (or signal). If any one (or more) of the above conditions is present, then the
framer will transmit an AIS alarm.
When automatic RAI generation is enabled (CCR2.4 = 1), the framer monitors the receive side to
determine if any of the following conditions are present: loss of receive frame synchronization, AIS alarm
(all one’s) reception, loss of receive carrier or if CRC4 multiframe synchronization (if enabled) cannot be
found within 128 ms of FAS synchronization. If any one (or more) of the above conditions is present,
then the framer will transmit a RAI alarm. RAI generation conforms to ETS 300 011 specifications and a
constant Remote Alarm will be transmitted if the framer cannot find CRC4 multiframe synchronization
within 400 ms as per G.706.
It is an illegal state to have both CCR2.4 and CCR2.5 set to one at the same time.
CCR3: COMMON CONTROL REGISTER 3 (Address=1B Hex)
(MSB)
(LSB)
TESE
TCBFS
TIRFS
–
RSRE
THSE
TBCS
RCLA
SYMBOL
POSITION
NAME AND DESCRIPTION
TESE
CCR3.7
Transmit Side Elastic Store Enable.
0=elastic store is bypassed
1=elastic store is enabled
TCBFS
CCR3.6
Transmit Channel Blocking Registers (TCBR) Function
Select.
0=TCBRs define the operation of the TCHBLK output pin
1=TCBRs define which signaling bits are to be inserted
TIRFS
CCR3.5
Transmit Idle Registers (TIR) Function Select. See Section
15 for details.
0=TIRs define in which channels to insert idle code
1=TIRs define in which channels to insert data from RSER
(i.e., Per Channel Loopback function)
–
CCR3.4
Not Assigned. Should be set to zero when written.
RSRE
CCR3.3
Receive Side Signaling Re–Insertion Enable. See Section 14
for details.
0=do not re–insert signaling bits into the data stream presented
at the RSER pin
1=re–insert the signaling bits into data stream presented at the
RSER pin