
Data Sheet
217
Rev. 1.2, 2006-01-26
QuadFALC
TM
PEF 22554 E
Functional Description T1/J1
During activation of the payload loop, the received 192 bits of payload data are looped back to the transmit
direction. The framing bits, CRC6 and DL-bits are not looped, if FMR4.TM = 0. They are originated by the
QuadFALC
TM transmitter. If FMR4.TM = 1 the received FS/DL-bit is sent transparently back to the line interface.
Following pins are ignored: XDI, XSIG, TCLK, SCLKX, SYPX and XMFS. All the received data is processed
normally. With bit FMR2.SAIS an AIS can be sent to the system interface on pin RDO.
Figure 94
Payload Loop (T1/J1)
5.7.4
Local Loop (T1/J1)
The local loop-back is activated by
The control bit LIM0.LL (LIM0_T) or
After detection of the appropriate In-band loop code, if enabled by ALS.SILS, see Chapter 5.5.7.
The local loop-back mode disconnects the receive lines RL1/2 or RDIP/RDIN from the receiver. Instead of the
signals coming from the line the data provided by system interface are routed through the analog receiver back to
the system interface. However, the bit stream is transmitted undisturbed on the line. An AIS to the distant end can
be enabled by setting FMR1.XAIS without influencing the data looped back to the system interface.
Note that enabling the local loop usually invokes an out of frame error until the receiver resynchronizes to the new
framing. The serial codes for transmitter and receiver have to be identical.
Figure 95
Local Loop (T1/J1)
5.7.5
Single Channel Loop-Back (loop-back of time slots) (T1/J1)
The channel loop-back is selected by LOOP.ECLB = 1 (LOOP_T).
Each of the 24 time slots can be selected for loop-back from the system PCM input (XDI) to the system PCM output
(RDO). This loop-back is programmed for one time slot at a time selected by register LOOP. During loop-back, an
ITS09748
Clock +
Data
Rec.
Framer
Elast.
Store
Trans.
Framer
RDO
XDI
RCLK
RL1
RL2
XL1
XL2
Recovery
SCLKX
SCLKR
MUX
AIS-GEN
Elast.
Store
ITS09749
RDO
XDI
RCLK
AIS-GEN
RL1
RL2
XL1
XL2
Framer
Rec.
Framer
Trans.
Store
Elast.
Recovery
Data
Clock +
MUX
Elast.
Store