Functional Descriptions ......
An in-band audio signalling system used for the communication of Address and Data
information using sequential tone signalling.
Sequential tone signalling has been adopted to national and international standard tonesets.
The CM1481 will operate to any one of the following tonesets in both frequency and tone-
length. The required toneset is selected at initial configuration from the selection shown below.
HSC
Hexadecimal
Sequential
Code
Tone No
(Hex)
EEA
CCIR
ZVEI 1
PZVEI
ZVEI 2
ZVEI 3
\DZVEI
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
1981
1124
1197
1275
1358
1446
1540
1640
1747
1860
1055
930
1981
1124
1197
1275
1358
1446
1540
1640
1747
1860
2400
930
2400
1060
1160
1270
1400
1530
1670
1830
2000
2200
2800
810
2400
1060
1160
1270
1400
1530
1670
1830
2000
2200
970
2400
1060
1160
1270
1400
1530
1670
1830
2000
2200
885
2200
970
1060
1160
1270
1400
1530
1670
1830
2000
825
810
810
740
2247
991
2247
991
970
2800
885
740
2600
885
885
680
2110
2400
2110
1055
2600
680
2600
680
970
2400
680
2600
Table 7 Tone Frequencies (in Hz)
To ensure all-system compatibility, the CM1481 has been designed to operate to the
following rules.
Operational
Rules
Base and other units working with the CM1481 must conform to these rules.
1 All calls, commands and interrogations to, and calls from, the CM1481 are prefixed
with a 5 (or 6)-tone HSC format Selcall Address.
2 Full international group-calling is possible to more than one user group via GROUP
and REPEAT tones.
3 A DATA FUNCTION tone “B” is appended after the Selcall address. No more than 4
adjacent DATA tones are allowed; if more than 4 are required, a DATA FUNCTION
tone should be inserted after every fourth DATA tone.
4 The DATA FUNCTION tone may be lengthened to twice the chosen toneset length
under the control of the Extended Data Tone command at initial configuration.
5 If in any tone sequence (address or data) one tone character is identical to the
preceding one, to prevent confusion at the decoder a REPEAT-tone [‘E’] must be
transmitted in its place.
21
CMLMICRO [ CML MICROCIRCUITS ]
