Sigtronics MRIM-2 - Manual (Page 4)

between the Module and radios should be soldered and insulated for
reliability. Do not use crimp type splices. Use a good quality electrical
tape or heat shrink tubing to cover the soldered connections.
* For the more popular radios of this type Sigtronics manufactures plug
in “Y” adapters to make these connections easy. Contact your Sigtronics
dealer for pricing and availability.
Connect the six wires from the Interface Cable to the appropriate
connections on the vehicle’s radio. Once that is done you will need to set
the Radio Transmit Microphone Level. Radio Transmit Microphone Level
(labeled RADIO TRANSMIT MIC LEVEL) adjustment is provided through
two small holes on the side of the Mobile Radio Interface Module. The
adjustment sets the microphone audio level going to the radio during
transmit. The Transmit Microphone Level adjustment will need to be
initially set to your particular radio. The level once set, should never need
adjustment again unless the type of radio used is changed. The following
simple procedures take you through the adjustment.
RADIO TRANSmIT mICROpHONE lEvEl:
Radio Transmit Microphone Level Adjustment can be made with a small,
flat blade screwdriver. Referring to Figure 3, the level adjustment is set
by two controls – a “HI/LO” RANGE switch and a rotary “ADJ” control.
Set the RADIO TRANSMIT MIC LEVEL RANGE switch to the “LO” position
(up). This is the default factory setting. Adjust the “ADJ” control clockwise
to increase the output level to the radio. Counter-clockwise rotation
decreases it. The basic adjustment concept is simple. You will be setting
the level and clarity of outgoing radio transmissions through the Mobile
Radio Interface Module headset, to match or exceed that of transmissions
using the radio’s standard hand microphone. To do this, you will need to
transmit and receive on the vehicle’s radio to a remote station. Arrange
to have someone nearby with a radio compatible to the radio you are
using with the Mobile Radio Interface Module. Then…
1. Turn on vehicle power as well as the radio.
2. Plug a headset into the headset jack. Put on the headsets and position
the boom mic close to the mouth, as is the practice with hand-held
microphones. Voice clarity is best when the mic is about 1/4 inch
away and slightly off center from the lips. Turn the volume control
on the headset, all the way up (clockwise).
3. With the radio’s hand mic, transmit as normal, to the remote
station. Transmit long enough so that the receiving station can
get “calibrated” to your transmission (voice) level.
4. Verify radio reception in the headset. If OK, use the PTT switch
for the headset to transmit to your receiving party. If receiving
station reports weak transmission, use the screwdriver to turn the
RADIO TRANSMIT MIC LEVEL ADJ clockwise a small amount. If they
report garbled, broken, or noisy transmissions, turn the RADIO
TRANSMIT MIC LEVEL ADJ counter-clockwise a small amount. Repeat
as necessary until the receiving party reports that transmissions
through the Mobile Radio Interface Module headset sound as good
or better than when using the radio hand microphone.
5. If the receiving party reports that your transmissions are still weak
with the TRANSMIT MIC LEVEL ADJ at the full clockwise position,
then switch the RADIO TRANSMIT MIC LEVEL RANGE switch to the
“HI” position (down) and repeat steps 3 and 4 above.
Once the level is set, also check radio operation with the vehicle’s engine
running. If radio reception and transmission through the Mobile Radio
Interface Module are fine, this completes the installation. If something
does not work correctly, check the following troubleshooting guide:
RADIO TRANSMIT MIC LEVEL
RANGE
LO
HI
ADJ
123
SPEAKER HI (2) VIOLET NOTE 1
(3) VIOLET NOTE 1
(5) WHITE NOTE 2
(11) WHITE / ORANGE
PTT SWITCH HEADSET JACK
RING TIP
BARREL NOTE 3
(12) GRAY
(10) BLUE
(6) WHITE NOTE 2
(1) BROWN
(4) BLACK
(8) GREEN
J1
P1
(7) RED
FUSE
(1 AMP)
SPEAKER LO
PTT HI
PTT LO
MIC HI
MIC LO
CHASSIS GROUND
+12
VOLTS DC
RADIO TRANSMIT MIC LEVEL
RANGE
LO
HI
ADJ
Notes:
1. Connect either violet wire to the radio speaker Hi output. Connect the remaining violet wire to speaker Low.
2. Connect either white wire to the radio push-to-talk (PTT) key line input. Connect the remaining white wire to
the PTT key line return (PTT Low)
3. If using a headset with a PTT switch on the shell, omit the PTT switch here and connect the white / orange
wire directly to the ring terminal of the headset jack.
Mobile Radio Interface Module Wiring Diagram
Mobile Radio Interface Module
Figure 2
Radio
Figure 3
page 4 Sigtronics MRIM-2 www.sigtronics.com