Tone Remotes are employed to remotely control transmitters. A remote may be located in the same building as the transmitter, or they may be separated by many miles and use telephone lines or microwave links to connect the transmitter with the tone remote.
Control signals and voice are sent from the tone remote, over the dedicated pathway, to the transmitter. It is necessary to install an interface board in the transmitter to convert the tone remote signals to actual channel and Push-to-Talk (PTT) functions.
| Standard Tone Remote Frequencies | Relative Levels | Tone Duration |
|
High Level 2175 Guard Tone
|
10 dbm
|
120 msec
|
|
1950 Hz Transmit F1 Function
|
0 dbm
|
40 msec
|
|
1850 Hz Transmit F2 Function
|
0 dbm
|
40 msec
|
|
2050 CTCSS Monitor Function
|
0 dbm
|
40 msec
|
|
Low Level Guard Tone
|
-20 dbm
|
20 msec
|
|
Voice Peaks
|
0 – 5 dbm
|
Other tones may be employed to provide additional functions. These other tones will use the same 0 dbm level and 40 msec timing as those shown above.
|
Tone Freq.
|
Function
|
Function
|
Function
|
|
1750
|
Receiver 2
|
Mute
|
|
|
1650
|
Receiver 2
|
Mute
|
|
|
1550
|
Max Squelch
|
Repeater Off
|
CTCSS On
|
|
1450
|
Min Squelch
|
Repeater On
|
CTCSS Off
|
|
1350
|
Freq. 3
|
CTCSS 1 Select
|
Option 1 On
|
|
1250
|
Freq. 4
|
CTCSS 2 Select
|
Option 1 Off
|
|
1150
|
CTCSS 3 Select
|
Option 2 On
|
|
|
1050
|
CTCSS 4 Select
|
Option 2 Off
|
Function Tones are sent as a separate item from the PTT signal. A Function Tone is sent at 0 dbm for 350 msec. While a PTT signal (2175) is sent at -10 dbm for the entire time the voice is being transmitted.
In this method, a guard tone of 2175 is sent at +10 dbm for 40 msec, followed by a function tone at 0dbm for 40 msec, which is then followed by a continuous PTT tone of 2175 at -20 for the entire duration of the voice transmission.