Preliminary Information
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
MH89790B
31 of CSTi0 contain Master Control Words 1 and 2
(MCW1, MCW2) which are used to set up the
interface feature as seen by the respective bit
functions of Tables 3 and 4.
BIT
7,
6,
5
&4
NAME
A(N),
B(N),
C(N)
& D(N)
DESCRIPTION
Transmit Signalling Bits for Channel N:
These bits are transmitted on the CEPT 2048 kbit/s
link in bit positions 1 to 4 of timeslot 16 in frame N, and are the A, B, C and D signalling bits
associated with telephone channel N. The value of N lies in the range 1 to 15 and refers to the
channel on the CSTi1 channel from which the bits are sourced, the telephone channel with which
the bits are associated and the frame on the CEPT link on which the bits are transmitted. For
example, the bits input on the CSTi1 pin on channel 3 are associated with telephone channel 3,
which is timeslot 3 of the CEPT link, and are transmitted on bits positions 1 to 4 of timeslot 16 in
frame 3 of each multiframe on the CEPT link . If bits B, C or D are not used they should be given
the values ‘1, 0‘ and ‘1‘ respectively. The combination ‘0000‘ for ABCD bits should not be used for
telephone channels 1 to 15 as this would interfere with multiframe alignment.
Transmit Signalling Bits for Channel N+15:
These bits are transmitted on the CEPT 2048
kbit/s link in bit positions 5 to 8 of timeslot 16 in frame N, and are the A, B, C and D signalling bits
associated with telephone channel N+15. The value of N lies in the range 1 to 15 and refers to
both the channel on the CSTi1 stream where the bits are supplied and the frame on the CEPT
link on which the bits are transmitted, and indirectly indicates the telephone channel with which
the bits are are associated. For example, the bits input on the CSTi1 pin on channel 3 are
associated with telephone channel 18, which is timeslot 19 of the CEPT link, and are transmitted
in bits positions 5 to 8 of timeslot 16 in frame 3 of each multiframe on the CEPT link .
3,
2,
1
&0
A(N+15),
B(N+15),
C(N+15)
& D(N+15)
Table 6. Channel Associated Signalling: Data Format for CSTi1 Channels 1 to 15
BIT
7
NAME
IU0
DESCRIPTION
International Use 0:
When CRC is disabled, this bit is transmitted on the CEPT 2048 kbit/s link
in bit position 1 of timeslot 0 of frame-alignment frames . It is reserved for international use and
should be kept at ‘1’ when not used. If CRC is enabled, this bit is not used.
Transmit Frame Alignment Signal Bits 2 to 8:
These bits are transmitted on the CEPT 2048
kbit/s link in bit positions 2 to 8 of timeslot 0 of frame-alignment frames. These bits form the
frame alignment signal and should be set to ‘0011011‘.
6-0
FAF2-8
Table 7. Frame-Alignment Signal: Data Format for CSTi1 Channel 16
BIT
7
NAME
IU1
DESCRIPTION
International Use 1:
When the CRC is disabled and SiMUX bit in MCW3 is disabled, this bit is
transmitted on the CEPT 2048 kbit/s link in bit position 1 of timeslot 0 of non-frame-alignment
frames . It is reserved for international use and should be kept at ‘1‘ when not used. If CRC is
enabled and SiMUX is disabled, this bit is transmitted in bit 1 of timeslot 0 for frame 13 and 15. If
both CRC and SiMUX are enabled, then this bit is not used.
Transmit Non-Frame Alignment Bit:
This bit is transmitted on the CEPT 2048 kbit/s link in bit
position 2 of timeslot 0 of non-frame-alignment frames . In order to differentiate between
frame-alignment frames and non-frame-alignment frames, this bit should be kept at ‘1‘.
Non-Frame Alignment Alarm:
This bit is transmitted on the CEPT 2048 kbit/s link in bit position
3 of timeslot 0 of non-frame-alignment frames . It is used to signal an alarm to the remote end of
the CEPT link. The bit should be set to ‘1‘ to signal an alarm and should be kept at ‘0‘ under
normal operation.
National Use:
These bits are transmitted on the CEPT 2048 kbit/s link in bit positions 4 to 8 of
timeslot 0 of non-frame-alignment frames . These bits are reserved for national use, and on
crossing international borders they should be set to ‘1‘.
6
NFAF
5
ALM
4-0
NU1-5
Table 8. Non-Frame-Alignment Signal: Data Format for CSTi1 Channel 17
4-195
MITEL [ MITEL NETWORKS CORPORATION ]
