Operating instructions

LOCAL OPERATION
3-70
Tones
Tones sub-mode
Audio tones and digital code signals are used for many purposes within radio communication
systems. The Service Monitor has a TONES mode accessed from the Tx TEST, Rx TEST, Dx
TEST and AF TEST modes.
This gives facilities for testing tone calling and control systems of the following types.
• Sequential Tones. A selective calling system using audio tones.
• CTCSS (Continuous Tone Coded Squelch System).
• DCS (Digitally Coded Squelch).
• DTMF (Dual Tone, Multi-Frequency).
• POCSAG (Post Office Code Standardization Advisory Group). A paging system
using digital signaling.
The tone mode is entered from the top level screen of any main mode, other than SYSTEM or
SPEC ANA.
Pressing the [Tones] key will display the screen shown in Fig. 3-20, Tones selection screen and
Tones mode receiver input level setting.
Fig. 3-20 Tones selection screen and Tones mode receiver input level setting
Observing tones signals in other test modes
The effect of any tones signaling on transmitters or receivers under test can be studied using any
test mode of the Service Monitor.
When a test mode is selected, (either by pressing the [Tx TEST] key, [Rx TEST] key etc. or by
pressing the [Return] key), while any tones signal is running continuously (CTCSS or DCS Tones
On; Sequential or DTMF continuous mode Sending), the tones will continue to be generated. See
the
Tones ON/OFF control section of each specific tones description.