DS2154
8 SIGNALING OPERATION
The DS2154 contains provisions for both processor-based (i.e., software based) signaling bit access and
for hardware-based access. Both the processor-based access and the hardware-based access can be used
simultaneously if necessary. The processor-based signaling is covered in Section 8.1 and the hardware
based signaling is covered in Section 8.2.
8.1 Processor-Based Signaling
The Channel Associated Signaling (CAS) bits embedded in the E1 stream can be extracted from the
receive stream and inserted into the transmit stream by the DS2154. Each of the 30 voice channels has
four signaling bits (A to D) associated with it. The numbers in parentheses () are the voice channels
associated with a particular signaling bit. The voice channel numbers have been assigned as described in
the ITU documents. Note that this is different than the channel numbering scheme (1 to 32) that is used in
the rest of the data sheet. For example, voice channel 1 is associated with time slot 1 (Channel 2) and
voice Channel 30 is associated with time slot 31 (Channel 32). There is a set of 16 registers for the
receive side (RS1 to RS16) and 16 registers on the transmit side (TS1 to TS16). The signaling registers
are detailed below.
RS1 TO RS16: RECEIVE SIGNALING REGISTERS (Address = 30 to 3F Hex)
(MSB)
0
A(1)
A(2)
A(3)
A(4)
A(5)
A(6)
A(7)
A(8)
(LSB)
0
0
0
X
Y
X
X
RS1 (30)
RS2 (31)
RS3 (32)
RS4 (33)
RS5 (34)
RS6 (35)
RS7 (36)
RS8 (37)
RS9 (38)
RS10 (39)
RS11 (3A)
RS12 (3B)
RS13 (3C)
RS14 (3D)
RS15 (3E)
RS16 (3F)
B(1)
B(2)
B(3)
B(4)
B(5)
B(6)
B(7)
B(8)
B(9)
B(10)
B(11)
B(12)
B(13)
B(14)
B(15)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
D(1)
D(2)
D(3)
D(4)
D(5)
D(6)
D(7)
D(8)
D(9)
D(10)
D(11)
D(12)
D(13)
D(14)
D(15)
A(16)
A(17)
A(18)
A(19)
A(20)
A(21)
A(22)
A(23)
A(24)
A(25)
A(26)
A(27)
A(28)
A(29)
A(30)
B(16)
B(17)
B(18)
B(19)
B(20)
B(21)
B(22)
B(23)
B(24)
B(25)
B(26)
B(27)
B(28)
B(29)
B(30)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
D(16)
D(17)
D(18)
D(19)
D(20)
D(21)
D(22)
D(23)
D(24)
D(25)
D(26)
D(27)
D(28)
D(29)
D(30)
A(9)
A(10)
A(11)
A(12)
A(13)
A(14)
A(15)
SYMBOL
POSITION
NAME AND DESCRIPTION
Spare Bits.
X
RS1.0/1/3
Y
RS1.2
RS2.7
Remote Alarm Bit (integrated and reported in SR1.6).
Signaling Bit A for Channel 1.
A(1)
D(30)
RS16.0
Signaling Bit D for Channel 30.
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