Codan Radio MT-4E Paging - Manual (Page 12)

USER GUIDE | MT-4E PAGING SYSTEMS
Chapter 1: Introduction to Paging Page 4
OTHER PROTOCOLS
PURC® (Paging Universal Remote Control)
Paging systems can use a tone remote control sequence called PURC® (designed by Motorola) to
allow a transmitter to be keyed on a specifi c channel and to select analog or digital mode operation.
PURC® uses a standard tone remote control sequence utilizing a High Level Guard Tone (2175 Hz),
Function Tone (1950 Hz), and Low Level Guard Tone (2175 Hz) as shown in Figure 1-1.
Figure 1-1: PURC® Tone Remote Sequence
The analog or digital mode of operation is determined by the presence (or absence) of the Low Level
Guard Tone. The Function Tone is used to select the transmitter channel (if used). PURC® tones are
within the standard audio band of 300 Hz to 3400 Hz and can be easily transmitted over an analog radio
link for remote keying of paging transmitters.
HIGH LEVEL
GUARD TONE
(HLGT)
FUNCTION
TONE
LOW LEVEL GUARD TONE (LLGT)
120 - 140 ms 40 ms 100 ms minimum
+5 dBm
-10 dB from HLGT
-30 dB from HLGT
Length of Transmit
LOW LEVEL GUARD TONE (LLGT)
AUDIO PAGING INFORMATION
SILENCE
350 ms
HIGH LEVEL
GUARD TONE
(HLGT)
FUNCTION
TONE
SILENT PAUSE
120 - 140 ms 40 ms 130 - 170 ms
+5 dBm
-10 dB from HLGT
Length of Transmit
DIGITAL PAGING DATA (MODEM)
SILENCE
350 ms
Analog Paging Sequence
Digital Paging Sequence