PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 236

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

Semiconductor Group
6.7
6.7.1
The examples below demonstrate the use of loop-backs #1 and #3.
Loop-back #1 (LT side)
Loop-back #3 (NT side)
For correct operation of this example it is assumed that the IEC-Q is not in the
power-down mode, i.e. FSC and DCL are present.
.
–––––>
<–––––
–––––>
<–––––
<–––––
–––––>
<––––– C/I DC
<––––– C/I AR
NT
NT
C/I RES
C/I DR
C/I ARL
C/I DC
C/I AR
C/I RES
Examples for Activating Test Loop-Backs
Examples for Analog Loop-Back Control
(1111
(1000
(0001
(0000
(1010
(1111
(1000
(0001
B
B
B
B
B
B
B
B
)
)
)
)
)
)
)
)
LT
C/I DI
C/I ARL
C/I AR
C/I ARM
C/I UAI
C/I RES
LT
C/I DI
(1111
(1111
(1000
(0111
(0001
(1010
(1001
236
B
B
B
B
B
B
B
)
)
)
)
)
)
)
–––––> ; NT in "Test" state
–––––>
<––––– ; Close loop-back #1
–––––> ; Activation proceeds in NT
–––––> ; and LT
–––––> ;
<––––– ;
; Close loop-back #3
; NT act. complete, #3 closed
; Open #3 and reset NT
;
;
Activation complete,
#1 closed
Open loop-back #1,
reset the IEC-Q
Data Sheet 01.99
Programming
PEB 2091
PEF 2091