DS21354/DS21554 3.3V/5V E1 Single-Chip Transceivers
9. SIGNALING OPERATION
The DS21354/DS21554 contain 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 9.1 and the
hardware based signaling is covered in Section 9.2. When referring to signaling, the voice-channel
numbering scheme is used.
9.1. 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 framer. Each of the 30 voice channels has four
signaling bits (A/B/C/D) associated with it. The numbers in parentheses () are the voice channel
associated with a particular signaling bit. The voice channel numbers have been assigned as described in
the ITU documents. Please 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
(LSB)
X
0
0
0
X
Y
X
RS1 (30)
RS2 (31)
RS3 (32)
RS3 (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)
A(1)
A(2)
A(3)
A(4)
A(5)
A(6)
A(7)
A(8)
A(9)
A(10)
A(11)
A(12)
A(13)
A(14)
A(15)
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)
B(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)
B(7)
A(16)
A(17)
A(18)
A(19)
A(20)
A(21)
B(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)
B(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)
B(22)
D(23)
D(24)
D(25)
D(26)
D(27)
D(28)
D(29)
D(30)
D(8)
D(9)
D(10)
D(11)
D(12)
D(13)
D(14)
D(15)
SYMBOL POSITION
NAME AND DESCRIPTION
X
Y
RS1.0/1/3 Spare Bits
RS1.2
RS2.7 1.
RS16.0
Remote Alarm Bit (integrated and reported in SR1.6)
Signaling Bit A for Channel 1
Signaling Bit D for Channel 30
A(1)
D(30)
56 of 124
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
