CM1481 Datasheet, PDF (21/24 Pages) ON Semiconductor – 2-Channel EMI Filter with ESD Protection for Headsets/Speakers

Functional Descriptions ......
HSC
Hexadecimal
Sequential
Code
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.
Tone No
(Hex)
EEA
CCIR
0
1981
1981
1
1124
1124
2
1197
1197
3
1275
1275
4
1358
1358
5
1446
1446
6
1540
1540
7
1640
1640
8
1747
1747
9
1860
1860
A
1055
2400
B
930
930
C
2247
2247
D
991
991
E
2110
2110
F
2400
1055
Table 7 Tone Frequencies (in Hz)
ZVEI 1
2400
1060
1160
1270
1400
1530
1670
1830
2000
2200
2800
810
970
885
2600
680
PZVEI
2400
1060
1160
1270
1400
1530
1670
1830
2000
2200
970
810
2800
885
2600
680
ZVEI 2
2400
1060
1160
1270
1400
1530
1670
1830
2000
2200
885
810
740
680
970
2600
ZVEI 3
\DZVEI
2200
970
1060
1160
1270
1400
1530
1670
1830
2000
825
740
2600
885
2400
680
Operational
Rules
To ensure all-system compatibility, the CM1481 has been designed to operate to the
following 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.
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