User's Manual

Operation
RFI-148 & RFI-900 High Output Power Paging Transmitters User Manual Page 26 of 134
The channel frequencies can be set anywhere within the radio switching bandwidth, but their difference from
the lower limit of the switching bandwidth must be an integer multiple of the raster frequency.
The channel to be used can be set by adjusting the current channel setting.
A channel width option of 6.25kHz is available, in addition to the regular 12.5kHz and 25kHz options, but this
“Ultra-Narrow” band option must be explicitly requested, by indicating “UN” in the product order code (refer
to Appendix F).
ENCODER CHANNEL CONTROL
The active channel can be set by adjusting the current channel setting in software. Alternatively, “Encoder
Channel Control” may be enabled and the channel set through the LIU interface as shown in Table 8 below
where N/C abbreviates Not Connected. If encoder channel control is used, the channel cannot be changed in
software.
Channel
CH4
CH3
CH2
CH1
1
N/C
N/C
N/C
N/C
2
N/C
N/C
N/C
Gnd
3
N/C
N/C
Gnd
N/C
4
N/C
N/C
Gnd
Gnd
5
N/C
Gnd
N/C
N/C
6
N/C
Gnd
N/C
Gnd
7
N/C
Gnd
Gnd
N/C
8
N/C
Gnd
Gnd
Gnd
9
Gnd
N/C
N/C
N/C
10
Gnd
N/C
N/C
Gnd
11
Gnd
N/C
Gnd
N/C
12
Gnd
N/C
Gnd
Gnd
13
Gnd
Gnd
N/C
N/C
14
Gnd
Gnd
N/C
Gnd
15
Gnd
Gnd
Gnd
N/C
16
Gnd
Gnd
Gnd
Gnd
Table 8: Channel selection via LIU Interface
4.3.3 Push-To-Talk (PTT)
There are three methods available to turn the transmitter on:
Encoder Interface -> Encoder Channel Control