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Data Sheet
195
Rev. 1.2, 2006-01-26
QuadFALC
TM
PEF 22554 E
Functional Description T1/J1
5.5.4
Errored Second (T1/J1)
The QuadFALC
TM supports the error performance monitoring by detecting the following alarms or error events in
the received data: framing errors, CRC errors, code violations, loss of frame alignment, loss-of-signal, alarm
indication signal, receive and transmit slips. With a programmable interrupt mask register ESM all these alarms or
error events can generate an Errored Second Interrupt (ISR3.ES) if enabled.
5.5.5
One-Second Timer (T1/J1)
A one-second timer interrupt can be generated internally to indicate that the enabled alarm status bits or the error
counters have to be checked. The one-second timer signal is output on port SEC/FSC if configured: For
GPC6.COMP_DIS = 0
B the register bits GPC1_T.FSS(1:0) are to configure the sources of FSC out of the 4 channels. For GPC6.COMP_DIS = 1
B the global GPC2 register is used instead of the GPC1 register in
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.
5.5.6
Clear Channel Capability (T1/J1)
For support of common T1 applications, clear channels can be specified through the 3-byte register bank
CCB(1:3). In this mode the contents of selected transmit time slots are not overwritten by internally or externally
sourced bit-robbing and zero code suppression (B7 stuffing) information. See also Chapter 5.3.3.
5.5.7
In-Band Loop Generation, Detection and Loop Switching (T1/J1)
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_T). 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_T). Programming of these patterns is done in registers LCR2 and LCR3
(LCR3_T). The pattern length is individually programmable in length from 5 to 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 5.7.2 and local loop, see
Chapter 5.7.4) 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