Codan Radio MT-3 - Manual (Page 39)

MT-3 ANALOG RADIO SYSTEMS | USER GUIDE
Chapter 5: Radio System Components Page 31
Channel Selection
An MT-3 crystal controlled radio modules operating frequency is selected by the control module’s
fundamental crystal frequency. The channel select lines and internal BCD rotary switches are not used
by the crystal control module.
MT-3 synthesized radio modules are capable of 16 channel operation. The 16 channels are controlled
via four CSEL signal lines connected to each receiver and transmitter module. The CSEL signal lines
are set as either a 0 (0 Vdc) or a 1 (+9.5 Vdc). Table 5-1 shows the channel selected for the CSEL input
settings. Bank select jumpers / connections are not used for MT-3 radio systems.
Table 5-1: Channel Selection Settings
Channel Decimal CSEL3 CSEL2 CSEL1 CSEL0
1 0 0 0 0 0
2 1 0 0 0 1
3 2 0 0 1 0
4 3 0 0 1 1
5 4 0 1 0 0
6 5 0 1 0 1
7 6 0 1 1 0
8 7 0 1 1 1
9 8 1 0 0 0
10 9 1 0 0 1
11 10 1 0 1 0
12 11 1 0 1 1
13 12 1 1 0 0
14 13 1 1 0 1
15 14 1 1 1 0
16 15 1 1 1 1
There are 3 different ways to change the channel of a transmitter / receiver module:
1 The user can set jumpers mounted on the motherboard for each Channel Select signal line (Set
of four for each Tx / Rx module). These jumpers can be used to permanently set a subrack slot
at a specifi c channel.
• Jumpers can be set for 0 (0 Vdc) “B” or “down” or 1 (+9.5 Vdc) “A” or “up”.
• Pull-up resistor jumpers to +9.5 Vdc must be installed.
2 CSEL signal lines can be controlled externally by a tone remote adapter, or other third party
devices.
3 Sixteen-position rotary select switches mounted on the front of the base controller can control the
CSEL lines. Optionally the Audio Control Card can have a rotary switch added.
The pull-up resistor jumpers to +9.5 Vdc must be removed and all channel select jumpers must be
installed in the 1 or “up” position for both external control and rotary switch control of channel selection.
The locations of the channel select and pull-up jumpers are shown in Figure 5-3.