MT9074AL Zarlink Semiconductor, Inc., MT9074AL Datasheet - Page 17

• Manufacturer Part Number: MT9074AL
• Description: T1/E1/J1 Single Chip Transceiver
• Manufacturer: Zarlink Semiconductor, Inc.

MT9074
E1 Digital Interface
PCM30 (E1) basic frames are 256 bits long and are
transmitted at a frame repetition rate of 8000 Hz,
which results in an aggregate bit rate of 256 bits x
8000/sec = 2.048 Mbits/sec. The actual bit rate is
2.048 Mbits/sec +/-50 ppm encoded in HDB3 format.
The HDB3 control bit (page 01H, address 15H, bit 5)
selects either HDB3 encoding or alternate mark
inversion (AMI) encoding. Basic frames are divided
into 32 time slots numbered 0 to 31, see Figure 34.
Each time slot is 8 bits in length and is transmitted
most significant bit first (numbered bit 1). This results
in a single time slot data rate of 8 bits x 8000/sec. =
64 kbits/sec.
It should be noted that the Mitel ST-BUS also has 32
channels numbered 0 to 31, but the most significant
bit of an eight bit channel is numbered bit 7 (see
Mitel Application Note MSAN-126). Therefore, ST-
BUS bit 7 is synonymous with PCM30 bit 1; bit 6 with
bit 2: and so on (Figure 34).
17
Frame #
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
1
2
3
4
5
6
7
8
9
Ft
1
0
1
0
1
0
1
0
1
0
1
0
Fs
0
0
0
1
1
1
0
0
0
1
1
1
Notes Frame #
R
e
n
h
o
n
a
o
n
d
a
a
s
y
c
z
r
t
t
i
i
Table 9 - SLC-96 Framing Structure(T1)
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Ft
1
0
1
0
1
0
1
0
1
0
1
0
Fs Notes Frame #
X
X
X
X
X
X
X
X
X
X
X
S
C
B
o
n
e
n
a
o
F
e
d
c
s
r
t
r
t
i
l
i
t
PCM30 time slot 0 is reserved for basic frame
alignment, CRC-4 multiframe alignment
communication of maintenance information. In most
configurations time slot 16 is reserved for either
Channel Associated Signaling (CAS or ABCD bit
signaling) or Common Channel Signaling (CCS). The
remaining 30 time slots are called channels and
carry either PCM encoded voice signals or digital
data. Channel alignment and bit numbering is
consistent
numbering. However, channels are numbered 1 to
30 and relate to time slots as per Table 10.
PCM30
Timeslots
Voice/Data
Channels
(DSTi/o
and
CSTi/o)
Table 10 - STBUS vs. PCM-30 to Channel
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
with
Ft
1
0
1
0
1
0
1
0
1
0
1
0
0 1,2,3...15
0 1,2,3...15
Relationship(E1)
time
Fs
C
C
C
S
S
A
A
S
L
L
L
L
C = Maintenance Field Bits
slot
L = Line Switch Field Bits
A = Alarm Field Bits
S = Spoiler Bits
S = Spoiler Bits
16
16
alignment
Notes
17,18,19,... 31
17,18,19,... 31
Data Sheet
and
and
the
bit