Data Sheet
June 2002
TMXF28155 Supermapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
509
Agere Systems Inc.
21 28-Channel Framer Block Functional Description
(continued)
21.16 Transmit Signaling Global Feature Provisioning
The transmit signaling processor requires the provisioning of one global item in order to enable signaling extraction
and delivery.
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Link Count (number of active transmit links).
21.16.1 Link-Count Selection
The link count is specified by programming FRM_T_LINKCNT[4:0] in FRM_SGR8 (
Table 378 on page 270
), bits
[14:10]. The reset value is 28, which is appropriate for a 28-link DS1 application. A value of 21 is appropriate for a
21-link CEPT application. If the application mixes DS1 and CEPT links or the TDM clock supplied to the framer is
less than 51.84 MHz, this value should match the terminal count (FRM_TC[7:0]) set in FRM_FGR2 (
Table 318 on
page 249
), bits [7:0].
21.17 Other Transmit Signaling Global Features
21.17.1 Support of Automatic Signaling Freeze on Framing Bit Errors
This feature is valid when extracting signaling from the receive line interface (transport mode). By default, signaling
extraction from a particular receive line will halt when the appropriate alignment has been lost. In order to guaran-
tee that signaling freeze takes place as soon as possible, FRM_T_AFZFBE in FRM_SGR8 (
Table 378 on
page 270
), bit 1, must be set to 1. When enabled, FRM_T_AFZFBE halts signaling extraction for 32 frames upon
detection of a frame bit error. When FRM_T_AFZFBE is enabled, the transmit signaling debounce feature must
also be enabled. The FRM_T_SIGDEB feature is enabled in FRM_TSLR32 (
Table 391 on page 277
), bit 5.
21.17.2 Support of Byte-Sync SONET Mapping
A provisionable feature related to SONET byte-sync mapping requires that those time slots which are configured
for no-signaling should have a signaling value of 0 transported by the VT mapper. This feature can be enabled by
setting FRM_T_SUBZERO in FRM_SGR8 (
Table 378 on page 270
), bit 5, to 1. In that case, those time slots with a
signaling state mode of no-signaling (GF = 10) will automatically forward a value of 0 to the VT mapper.
21.18 Transmit Signaling Status Registers
There are two status values that are maintained for each of the links.
21.18.1 Maintenance of CEPT Related Status Bits
There are 2 bits which reflect the status of the CEPT time slot 16 signaling multiframe. These status bits are valid
when the source of signaling is set to be the receive line interface (transport mode). The location of these status
bits is in FRM_TSLR33, Transmit Signaling Link Register 33 (COR)
Table 390 on page 277
.
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The receive signaling register searches for AIS in time slot 16 when time slot 16 alignment is lost. The status of
this search is maintained.
I
The status of TS16 multiframe alignment is maintained.