ZETRON 15P, Руководство по эксплуатации

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7-1
7. QUICK REFERENCE
UNDERSTANDING THE TWO-TONE CODING SYSTEM
This is a brief guide to the two-tone coding system. It defines the terminology, such as “tone
group” and “code plan”, and tells how to use the coding charts to determine the tone
frequencies of a certain two-tone pager.
The Reeds
The first step in understanding the two-tone coding system is understanding the
distinguishing characteristics of a two-tone sequential pager. Two-tone pagers contain two
reeds or active filters tuned to specific frequencies. These reeds can be referred to as the A
reed and the B reed. They set off the pager's alerting mechanism (e.g. bell or vibrator) or
open the receiver for a voice transmission when they detect tone A followed by tone B over
the radio channel.
Tone Groups
To coordinate paging equipment, standardized sets of frequencies and timings for the A and
B tones have been developed by pager manufacturers such as Motorola and GE. Two-tone
sequential pagers use the 140 tones that fall between 288.5 Hz and 2468.2 Hz. For
organizational purposes, these 140 tones have been divided into the 14 tone groups. Eight
standard timings have also been established. These tone groups and timings are shown in
Table 7-1or Table 7-2.
Motorola and GE Tone Group Frequencies
Table 7-1 Zetron Tone Groups 1 to 7
Zetron Group No.
Mfr. Tone Groups
1
Mot 1
2
Mot 2
3
Mot 3
4
Mot 4
5
Mot 5
6
Mot 6
7
Mot A
T 0
330.5 569.1 1092.4 321.7 553.9 1122.5 358.9
O 1 349.0 600.9 288.5 339.6 584.8 1153.4 398.1
N 2 368.5 634.5 296.5 358.6 617.4 1185.2 441.6
E 3 389.0 669.9 304.7 378.6 651.9 1217.8 489.8
4 410.8 707.3 313.0 399.8 688.3 1251.4 543.3
N 5
433.7 746.8 953.7 422.1 726.8 1285.8 602.6
U 6 457.9 788.5 979.9 445.7 767.4 1321.2 668.3
M 7
483.5 832.5 1006.9 470.5 810.2 1357.6 741.3
B 8 510.5 879.0 1034.7 496.8 855.5 1395.0 822.2
E 9
539.0 928.1 1063.2 524.6 903.2 1433.4 912.0
R
Diagonal
569.1 979.9 569.1 569.1 979.9 979.9 979.9