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QuadFALC
TM
PEF 22554 E
Functional Description E1
Data Sheet
138
Rev. 1.2, 2006-01-26
on RSIG is transmitted in the last 4 bits per time slot and is aligned to the data on RDO. The first 4 bits per time
slot can be optionally fixed high or low (SIC2.SSF), except for time slot 0 and 16 (bit 1 to 4 are always "0000" in
TS16). In time slot 0 the FAS/NFAS word is transmitted, in time slot 16 the CAS multiframe pattern "0000XYXX".
Data on RSIG is only valid if the freeze signaling status is inactive. With FMR1.SAIS an all-ones data stream can
be transmitted on RDO and RSIG. The signaling procedure is done as it is described in ITU-T G.704 and G.732.
The main functions are:
Synchronization to a CAS multiframe
Detection of AIS and remote alarm in CAS multiframes
Separation of CAS service bits X1 to X3
Updating of the received signaling information is controlled by the freeze signaling status. The freeze signaling
status is automatically activated if a loss-of-signal (FRS0.LOS = 1), or a loss of CAS multiframe alignment
(FRS1.TSL16LFA = 1) or a receive slip occurs. The current freeze status is output on port FREEZE (RPA, RPB
or RPC) and indicated by register SIS.SFS. Optionally automatic freeze signaling can be disabled by setting bit
SIC3.DAF.
After CAS resynchronization an interrupt is generated. Because at this time the signaling is still frozen, CAS data
is not valid yet. Readout of CAS data has to be delayed until the next CAS multiframe is received.
Because the CAS controller is working on the system interface (pcm highway) side of the receive buffer, slips
disturb the CAS data.
Figure 46
2.048 MHz Receive Signaling Highway (E1)
4.3.5.2
Serial Transmit CAS (E1)
In serial CAS mode the signaling data received on port XSIG is sampled with the working clock of the transmit
system interface (SCLKX) in combination with the transmit synchronization pulse (SYPX), see Chapter 4.6. Data
on XSIG is latched in the bit positions 5 to 8 per time slot, bits 1 to 4 are ignored. Time slots 0 and 16 are sampled
completely (bit 1 to 8). The received CAS multiframe is inserted frame aligned into the data stream on XDI and
must be valid during the last frame of a multiframe if CRC4/multiframe mode is selected. The CAS multiframe is
aligned to the CRC4-multiframe; other frames are ignored. Data sourced by the internal signaling controller (
P
access mode) overwrites the external signaling data.
If the QuadFALC
TM is configured for no signaling, the system interface data stream passes through the
QuadFALC
TM undisturbed.
Note: CAS data on XSIG is read in the last frame of a multiframe only and ignored in all other frames.
F0133
A B C D
4 5 6 7
0 1 2 3 4 5 6 7
TS31
TS0
TS1
0 0 0 0 X Y X X
0 1 2 3 4 5 6 7
TS16
A B C D
0 1 2 3 4 5 6 7
TS31
RSIG
RDO
SCLKR
FAS/NFAS
SYPR
T
125 s
T
= Time slot offset (RC0, RC1)
FAS
= Frame alignment signal
NFAS
= TS0 not containing FAS
ABCD
= Signaling bits for time slots 1...15 and 17...31 of CAS multiframe
0000XYXX
= CAS multiframe alignment signal in TS16