7K • Chapter 4
4-34
the tone sine wave in microseconds. Tone codes may be either taken from the
Tone Code Table or calculated.
Tone Code Table Explained
The Tone Code Table was created to simplify your programming efforts by
listing frequencies from 100Hz to 3KHz (in 5Hz increments), and the
appropriate tone code for each frequency. The complete Tone Code Table
begins on page A-20 and look similar to this:
Tone Code Table (continued)
All Frequencies in Hz
Freq Code Freq Code Freq Code Freq Code Freq Code
100 9999 225 4444 350 2857 475 2105 600 1666
105 9523 230 4347 355 2816 480 2083 605 1652
110 9090 235 4255 360 2777 485 2061 610 1639
115 8695 240 4166 365 2739 490 2040 615 1626
120 8333 245 4081 370 2702 495 2020 620 1612
Note: Most radio systems have a response of 300Hz to 3KHz, and will not pass
tone frequencies outside this range.
Calculating Tone Codes
If you wish to program a tone frequency that is not listed in the Tone Code
Table, you will need to calculate its tone code. (This is particularly true of
paging tones, which are specified to tenths of Hertz.) To assist you in
calculating your tone codes, the following explanation is offered.
To determine your tone code, simply take the reciprocal of the tone frequency.
It is easily done on a calculator:
• Enter 1,000,000, then divide this number by the tone frequency in Hertz.
• The quotient, rounded off to a 4-digit whole number, is the tone code.
• If the result is 999 or less, you must insert a leading zero.
Here are some examples:
• The tone frequency is 1200Hz. What is the tone code? Dividing 1,000,000
by 1200 yields 833.3, so the tone code is 0833.
• The tone frequency of a single-tone page is 1050Hz.What is the tone code?
Dividing 1,000,000 by 1050 yields 952.4, so the tone code is 0952.
• The tone frequency is 398.1Hz. What is the tone code? Dividing 1,000,000
by 398.1 yields 2511.9, so the tone code is 2512.
To Next Page
Loading...