Codan Radio MT-3 - Manual (Page 24)

USER GUIDE | MT-3 ANALOG RADIO SYSTEMS
Chapter 3: Analog Radio System Confi gurations Page 16
BASE STATION (OR REPEATER-BASE) OPERATION
The MT-3 modules may be confi gured to operate in a base station confi guration, such as a tone remote
controlled base station, dual base stations or repeater-base system (repeater with external control)
using the AC-3E control card. The system could also be confi gured as a single base station with a
separate single repeater in the same subrack. The AC-3E allows jumper selectable connections from
RXA to TXA and/or TXB and RXB to TXA and/or TXB (any receiver to any transmitter), as well as
external connections for both pairs of receivers and transmitters.
The receivers, transmitters, AC-3E control card and tone remote adapter are shown in Figure 3-4.
Figure 3-4: MT-3 Analog Base Station system shown with two pairs of transceivers and two tone remote adapters
The AC-3E control card is hardware jumpered to control the interconnection between the modules, as
well as the interconnection to external equipment. This allows the user to select the operation of this
system (single base, dual base, repeater-base, dual repeater-base) by setting jumpers.
The AC-3E is jumper selectable to allow for fi ltering of the CTCSS tones in the control card. The voice
band fi lter in the receivers can be enabled for additional CTCSS fi ltering if required, or to remove the
CTCSS tones from the System Regulator speaker.
The Telex DSP-223 tone-remote adapter provides the means of remotely controlling Codan base stations
and repeaters. The adapters can be used in conjunction with tone-remote control consoles which use
the industry-standard sequential tone keying format. The DSP-223 adapters are interconnected to the
distant remote control console(s) by any analog voice grade transmission medium such as a microwave
link, a leased telephone line, or a twisted-pair 600-ohm line.
The motherboard carries the outgoing signals from the receiver, through the controller to the external
equipment (and/or the transmitter(s) in repeat operation). Signals from the external equipment are
routed through the controller to the transmitter(s). The signals on the motherboard are COR, PTT,
Balanced Audio, Receiver Discriminator Audio, Receiver Mute and Transmitter Subtone Input.
The AC-3E has a current draw of less than 30 mA. The optional CTCSS decoders / encoders have a
current draw of less than 13 mA each. The Telex DSP-223 has a current draw of less than 500 mA.
TELEX
PROGRAMMING PORT
DSP-223
PTT IC
HANDSET
POWER PTT MONITOR
FUNCTION
CTCSSLINE RX LINE TX
+
RADIO TX
+
RADIO RX LINE TX LINE RX RADIO TXRADIO RXCTCSS RADIO TX
-
GROUND LINE TX
-
TELEX
PROGRAMMING PORT
DSP-223
PTT IC
HANDSET
POWER PTT MONITOR
FUNCTION
CTCSSLINE RX LINE TX
+
RADIO TX
+
RADIO RX LINE TX LINE RX RADIO TXRADIO RXCTCSS RADIO TX
-
GROUND LINE TX
-
5 7
5 7
AUDIO
CONTROL
RX A
RX B
TX A
TX B
TX A
TX B
5
9
13
5
9
13
PULL DOWN
TO REMOVE
T X
REFERENCE
INPUT
OFF
KEY TX
MIC
RF OUT
NORM
TRANSMITTER
FREQUENCY (MHz)
MADE IN CANADA
MODEL # CODE
SQ . DI SA B L E
N
O
RM O
F F
RF N I
REFERENCE
INPUT
RECEIVER
FREQUENCY (MHz)
MADE IN CANADA
MODEL # CODE
T X
REFERENCE
INPUT
OFF
KEY TX
MIC
RF OUT
NORM
TRANSMITTER
FREQUENCY (MHz)
MADE IN CANADA
MODEL # CODE
SQ . DI SA B L E
N
O
RM O
F F
RF N I
REFERENCE
INPUT
RECEIVER
FREQUENCY (MHz)
MADE IN CANADA
MODEL # CODE
2
1
5
4
3
6 7
8
11
10
9
FUNCTION
12
SYSTEM REGULATOR
MADE IN CANADA
VOL METER
+
-
ON
OFF
SPKR
INT
EXT
EXT
SPKR
ANTENNA A ANTENNA B
RX A RX B
TX A TX B