
PSB 2115
PSF 2115
Functional Description
Semiconductor Group
76
11.97
2.4.4.3
The loop-back register controls all analog (S/T-interface) and digital (IOM-2 interface)
loop-backs. Additionally the wake-up mode can be programmed.
MON-8 Loop-Back Register
Value after Reset: 02
H
.
Address: 2h
AST
SB1
SB2
SC
IB1
IB2
1
IB12
RD/WR
AST
Asynchronous Timing.
Defines the length of the Timing signal (DU = 0) on IOM-2. If synchronous 
timing is selected (AST=0) the IPAC in LT-S mode will issue the timing 
request only in the C/I channel of the selected timeslot (C/I = 0000b). This 
mode is useful for applications where IOM-2 clock signals are not switched 
off. Here the IPAC can pass the TE initiated activation via C/I = 0000b in 
IOM-2 cannel 0 upstream to the U-interface device. In case IOM-2 clocks 
can be turned off during power-down or the LT-S IPAC is pin-strapped to a 
different timeslot than the U-interface device, synchronous timing signals 
will not succeed in waking the U-interface device. Under these 
circumstances asynchronous timing needs to be programmed (AST=1). 
Here the line DU is set to ZERO for a period long enough to wake any U-
interface device, independent of timeslot or clocks. Typically asynchronous 
timing is programmed for intelligent NT applications (IPAC pin-strapped to 
LT-S with NT state machine).
Note:
The asynchronous timing option is restricted to configurations with the IPAC 
operating with NT state machine (i.e., LT-S pin-strap & FSMM bit 
programmed).
Closes the loop-back for B1 channel data close to the activated S/T-
interface (i.e., loop-back IOM-2 data) in LT-S mode.
Closes the loop-back for B2 channel data close to the activated S/T-
interface (i.e., loop-back IOM-2 data) in LT-S mode.
Close complete analog loop-back (2B+D) close to the S/T-interface. 
Corresponds to C/I = ARL. Transparency is optional. Operational in LT-S 
mode.
Close the loop-back for B1 channel close to the IOM-2 interface (i.e. loop-
back S/T data). Transparent. IB1 and IB2 may be closed simultaneously.
SB1
SB2
SC
IB1