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Data Sheet
151
Rev. 1.2, 2006-01-26
QuadFALC
TM
PEF 22554 E
Functional Description E1
GPC6.COMP_DIS = 0
B the register bits GPC1_E.FSS(1:0) are to configure the sources of FSC out of the 4 channels. For GPC6.COMP_DIS = 1
compatibility mode.
Optionally synchronization to an external second timer is possible which has to be provided on pin SEC/FSC.
Selecting the external second timer is done with GCR.SES.
Configuration of the pin SEC/FSC is done by GPC1.CSFP.
4.5.6
In-Band Loop Generation, Detection and Loop Switching (E1)
In-band Signaling is an unchannelized signaling method. All data bits of all time slots of a frame can be used by
the In-band signaling information.
Detection and generation of In-band Loop code is supported by the QuadFALC
TM on the line side and on the
system side independent from another.
The QuadFALC
TM generates and detects framed or unframed In-band codes. The so called loop-up code (for loop
activation) and loop-down code (for loop deactivation) are recognized. If the 1. bit of a frame (frame bit) is used for
In-Band signaling it is the so called “unframed” signaling, otherwise it is called “framed” signaling. The selection
between framed or unframed in-band loop code is done by LCR1.FLLB.
The maximum allowed bit error rate within the loop codes can be up to 10
-2 for proper detection of the loop codes.
One “In-band loop sequence” consists of a bitsequence of 51200 consequtive bits. The In-band loop code
detection is based on the examination of such “In-band loop sequences”.
The following In-band loop code functionality is performed by the QuadFALC
TM:
The necessary reception time of In-band loop codes until an automatic loop switching is performed is
configured for the system side by the register bits INBLDTR.INBLDT(1:0) (INBLDTR_E). Configuring for the
line side is done by INBLDTR.INBLDR(1:0). If for example INBLDTR.INBLDR(1:0) = 00
B a time of 16 “In-band
loop sequences” (16 x 51200 bits) is selected for the line side.
The interrupt status register bits ISR6.(3:0) reflects the type of detected In-band loop code. Masking can be
done by IMR6(3:0). The status bits are set after one “In-band loop sequence” is detected (no dependency on
INBLDTR).
Transmission of In-Band loop codes is enabled by programming FMR3.XLD/XLU. Transmission of codes is
done by the QuadFALC
TM for at least 5 seconds.
The QuadFALC
TM also offers the ability to generate and detect user defined In-band loop-up and loop-down
patterns (LCR1.LLBP = 1) (LCR1_E). Programming of these patterns is done in registers LCR2 and LCR3
(LCR3_E). The pattern length is individually programmable in length from 5to 8 bits by LCR1.LAC(1:0) and
LCR1.LDC(1:0). A shorter pattern can be inplemented by configuring a repeating pattern in the LCR2 and
LCR3.
Automatic loop switching (activation and deactivation, for remote loop, see Chapter 4.7.2 and local loop, see
Chapter 4.7.4) based on In-band Loop codes can be done. Two kinds of line loop back (LLB) codes are
defined in ANSI-T1.403, 1999 in chapter 9.4.1.1 and 9.4.1.2. respectively. Automatic loop switching must be
enabled through configuration register bits ALS.SILS for the In-Band Loop codes coming from the system side
and ALS.LILS for the In-Band Loop codes coming from the line side respecively. Masking of ISR6.(3:0) for
interrupt can be done by register bits IMR6.(3:0). The interrupt status register bits ISR6.(3:0) (ISR6_E) will be
set to 1
B if an appropriate In-Band code were detected, independent if automatic loop switching is enabled.
(Because the controller knows if automatic loop switching is enabled, it knows if a loop is activated or not.)
Code detection status only for the line side is displayed in status register bits RSP.LLBDD and RSP.LLBAD.
Detection and generation of In-Band Loop code is supported on line and system side independent from each other
.
Framed and unframed In-Band loop code can be generated and detected.
Automatic loop switching is logically ORd with the appropriate loop switching by register bits.
If a remote loop is activated by an automatic loop switching the register bit LIM0.JATT controls also if the jitter
attunator is active or not, see also Figure 35.
If ALS.LILS is set (ALS_E), the remote loop is activated after an activation In-Band loop code (see ANSI T1 404,
chapter 9.4.1.1.) is detected from the line side and if the local loop is not activated by LIM0.LL = 1
B. The remote
loop is deactivated after a deactivation In-Band loop code (see ANSI T1 404, chapter 9.4.1.2.) is detected from