Owner's manual
DS2180A
041995 14/36
RECEIVE CONTROL REGISTER Figure 12
(MSB) (LSB)
ARC OOF RCI RCS SYNCC SYNCT SYNCE RESYNC
SYMBOL POSITION NAME AND DESCRIPTION
ARC RCR.7 Auto Resync Criteria.
0 = Resync on OOF or RCL event.
1 = Resync on OOF only.
OOF RCR.6 Out-of-frame (OOF) Condition Detection.
0 = 2 of 4 framing bits in error.
1 = 2 of 5 framing bits in error.
RCI RCR.5 Receive Code Insert. When set, the receive code selected by RCR.4 is
inserted into channels marked by RMR registers. If clear, no code is in-
serted.
RCS RCR.4 Receive Code Select.
0 = Idle code (7F Hex).
1 = Digital milliwatt.
SYNCC RCR.3 Sync Criteria. Determines the type of algorithm utilized by the receive syn-
chronizer and differs for each frame mode.
193S Framing (CCR.4=0).
0 = Synchronize to frame boundaries using F
T
pattern, then search for mul-
tiframe by using F
S
.
1 = Cross couple F
T
and F
S
patterns in sync algorithm.
193E Framing (CCR.4=1).
0 = Normal sync (utilizes FPS only).
1 = Validate new alignment with CRC before declaring sync.
SYNCT RCR.2 Sync Time. If set, 24 consecutive F-bits of the framing pattern must be
qualified before sync is declared. If clear, 10 bits are qualified.
SYNCE RCR.1 Sync Enable. If clear, the transceiver will automatically begin a resync if
two of the previous four or five framing bits were in error or if carrier loss is
detected. If set, no auto resync occurs.
RESYNC RCR.0 Resync. When toggled low to high, the transceiver will initiate resync im-
mediately. The bit must be cleared, then set again for subsequent resyncs.
RECEIVE CODE INSERTION
Incoming receive channels can be replaced with idle (7F
Hex) or digital milliwatt (µ-LAW format) codes. The re-
ceive mark registers indicate which channels are in-
serted. When set, bit RCR.5 serves as a “global” enable
for marked channels and bit RCR.4 selects inserted
code format: 0 = idle code, 1 = digital milliwatt.
RECEIVE SYNCHRONIZER
Bits RCR.0 through RCR.3 allow the user to control op-
erational characteristics of the synchronizer. Sync algo-
rithm, candidate qualify testing, auto resync, and com-
mand resync modes may be altered at any time in
response to changing span conditions.