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____________________________________________________ DS34T101, DS34T102, DS34T104, DS34T108
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Table 10-40. Registers Related to Signaling
Register Name
Description
Functions
Page
Tx Signaling Registers 1 to 16
Tx ABCD signaling to be inserted
Tx Signaling Insertion Enable Registers 1 to 4
Tx per-channel SW sig. insert controls
Tx Hardware Signaling Channel Select 1 to 4
Tx per-channel HW sig. insert controls
Rx Signaling Control Register
Rx auto and manual signaling freeze
Rx Signaling All-Ones Insertion Registers 1 to 3
Rx per-channel sig. all-1s insertion
Rx Signaling Registers 1 to 16
Rx ABCD signaling bits received
Rx Signaling Status Registers 1 to 4
Rx per-channel sig. change status
Rx Signaling Change of State Enable 1 to 4
Rx per-channel sig. interrupt enables
Rx Latched Status Register 4
Rx top-level sig. change latched status
Rx Interrupt Mask Register 4
Rx top-level sig. change interrupt mask
Rx Signaling Reinsertion Registers 1 to 4
Rx per-channel reinsertion control
10.11.3.1 Transmit Signaling Operation
There are two methods to provide transmit signaling data: software (i.e. from the
TS registers) and hardware (i.e.
from the formatter’s TSIG input). Both methods may be used simultaneously. The methods are described in the
subsections below.
10.11.3.1.1 Software Signaling
In the software signaling method, signaling data is loaded into the transmit signaling registers (
TS1 -
TS16) by the
CPU. Each transmit signaling register contains the signaling bits for two DS0 timeslots. On multiframe boundaries,
the signaling bits stored in these registers are loaded into a shift register for placement in the appropriate bit
position in the outgoing data stream. The CPU can watch for the setting of the
TLS1.TMF latched status bit on
multiframe boundaries to know when to update any Tx signaling bits that may need to be changed.
Signaling data can be sourced from the TS registers on a per-channel basis by using the
TSSIE registers.
In T1 ESF framing mode, there are four signaling bits per channel (A, B, C, and D).
TS1 -
TS12 contain a full
multiframe of signaling data. In T1 D4 framing mode, there are only two signaling bits per channel (A and B), and
the C and D bit positions in the
TS registers are ignored. In T1 mode, software signaling is enabled by setting
TCR1-T1.TSSE=1. When software signaling is enabled, signaling bits are sourced from the
TS registers for each
channel where the appropriate bit is set to 1 in the
TSSIE registers.
In E1 mode, timeslot 16 carries the signaling information. This information can be in either CCS (Common Channel
Signaling) or CAS (Channel Associated Signaling) format. Only CAS is supported by the signaling logic described
in this section. In E1 mode the
TCR1-E1.T16S bit specifies how Tx signaling is sourced. When T16S=1, CAS
signaling bits for all timeslots is unconditionally sourced from the
TS registers. When T16S=0, signaling bits are
sourced from the
TS registers for each channel where the appropriate bit is set to 1 in the
TSSIE registers. This
latter mode allows some signaling data for some channels to be sourced from the
TS registers while signaling data
for other channels can be sourced from the formatters TSIG input (hardware-based signaling).
Note that in E1 the 32 timeslots are referenced by two different channel number schemes in E1. In “channel”
numbering, TS0 through TS31 are labeled channels 1 through 32. In “phone channel” numbering, TS1 through
TS15 are labeled channels 1 through 15, and TS17 through TS31 are labeled channels 16 through channel 30.
This is illustrated below.
Table 10-41. Timeslot Number Schemes
TS
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Channel 1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Phone
Channel
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30