MT8979
ISO-CMOS
DSTi timeslots 1 and 17. Channel 16 contains the
frame alignment signal, and channel 17 contains the
non-frame alignment signal (see Figure 4). Channel
18 contains the Master Control Word 3 (see Table 9).
Figure 11 shows the relationship between the control
stream (CSTi1) and the CEPT stream.
Control Output (CSTo)
Control ST-BUS output (CSTo) contains the
multiframe signal from timeslot 16 of frame 0 (see
Table 10). Signalling bits A, B, C & D for each CEPT
channel are sourced from timeslot 16 of frames 1-15
and are output in channels 1-15 on CSTo , as shown
in Table 11. The
frame alignment signal and
nonframe alignment signal, received from timeslot 0
of alternate frames, are output in timeslots 16 and 17
as shown in Tables 12 and 13.
Channel 18 contains a Master Status Word, which
provides to the user information needed to determine
the operating condition of the CEPT interface i.e.,
frame synchronization, multiframe synchronization,
frame alignment byte errors, slips, alarms, and the
logic of the external status pin (see Table 14). Figure
12, shows the relationship between the control
stream channels and the CEPT signalling channels
in the multiframe. The ERR bit in the Master Status
word is an indicator of the number of errored frame
alignment bytes that have been received in alternate
timeslot zero. The time interval between toggles of
Timeslot Zero
1
C
1
0
C
2
0
C
3
1
C
4
0
C
1
1
C
2
1
C
3
Si1
(3)
C
4
Si2
(3)
Control Input 0 (CSTi0)
All the necessary control and signalling information
is input through the two control streams. Control
ST-BUS input number 0 (CSTi0) contains the control
information that is associated with each information
channel. Each control channel contains the per
channel digital attenuation information, the individual
loopback control bit, and the voice or data channel
identifier, see Table 2. When a channel is in data
mode (B7 is high) the digital attenuation and
Alternate Digit Inversion are disabled. It should be
noted that the control word for a given information
channel is input one timeslot early, i.e., channel 0 of
CSTi0 controls channel 1 of DSTi. Channels 15 and
31 of CSTi0 contain Master Control Words 1 and 2,
which are used to set up the interface feature as
seen by the respective bit functions of Tables 3 and
4.
Control Input 1 (CSTi1)
Control ST-BUS input stream number 1 (CSTi1)
contains the synchronization information and the A,
B, C & D signalling bits for insertion into timeslot 16
of the CEPT stream (refer to Tables 5 to 8). Timeslot
0 contains the four zeros of the multiframe alignment
signal plus the XYXX bits (see Figure 5). Channels 1
to 15 of CSTi1 contain the A, B, C & D signalling bits
as defined by the CEPT format (see Figure 5), i.e.,
channel 1 of CSTi1 contains the A,B,C & D bits for
Multiple Frame
Component
CRC
Frame #
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Frame Type
Frame Alignment Signal
Non-Frame Alignment Signal
2
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
3
0
A
(1)
0
A
(1)
0
A
(1)
0
A
(1)
0
A
(1)
0
A
(1)
0
A
(1)
0
A
(1)
4
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
5
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
6
0
Sn
(2)
0
Sn
(2)
0
Sn
(2)
0
Sn
(2)
0
Sn
(2)
0
Sn
(2)
0
Sn
(2)
0
Sn
(2)
7
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
8
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
1
Sn
(2)
S
M
F
I
Frame Alignment Signal
Non-Frame Alignment Signal
Frame Alignment Signal
Non-Frame Alignment Signal
Frame Alignment Signal
Non-Frame Alignment Signal
Frame Alignment Signal
S
M
F
I
I
Non-Frame Alignment Signal
Frame Alignment Signal
Non-Frame Alignment Signal
Frame Alignment Signal
Non-Frame Alignment Signal
Frame Alignment Signal
Non-Frame Alignment Signal
Figure 6 - CRC Bit Allocation and Submultiframing
Note 1 : Remote Alarm. Keep at 0 for normal operation.
Note 2 : Reserved for National use. Keep at 1 for normal operation.
Note 3 : Used to monitor far-end CRC error performance.
4-166
indicates position of CRC-4
multiframe alignment signal
MITEL [ MITEL NETWORKS CORPORATION ]
