Midian TRA, Instruction Manual

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Installation Instructions
3
Midian products utilize CMOS integrated circuits, which are susceptible to damage from high static charges. Be sure to
follow standard anti-static procedures when handling, including using grounded work stations and soldering irons and
wearing grounding bracelets. Please be careful when selecting wire colors. It is sometimes difficult to distinguish
between the grey, black, and brown wire colors under fluorescent lighting. We suggest using Color-Bright/Color-
Corrected or incandescent lighting. If in doubt, compare wire positions on board layout for correct color code.
Wire Function Instructions
Black Ground (P1 Pin 1) Connect to nearest ground point.
Red
11-16 VDC (P1 Pin 9) Connect to switched B+ in radio.
Grey
COR/COS Busy Lockout
(P1 Pin 3) Connect to point in Squelch or CTCSS circuit that changes logic level
when a carrier is received. Program desired polarity in
System
Parameters . A radio whose squelch circuit provides a logic low or a
logic high can readily turn the COR transistor on and off.
Orange
RX/Tone Input (P1 Pin 11) Normally connect to a squelched point in the receiver. Alternately
connect to an unsquelched audio point, usually the high side of the
volume control or discriminator output, if squelch input is used.
Light brown Squelch Output (P1 Pin 5) Optional. Connect to point in radio's squelch circuit that normally
changes logic level with carrier. The polarity is set by selecting polarity
of squelch diode D3 using JU7. Resistor R88 can be changed to provide
more or less current. Do not conflict with grey lead. This lead is not
necessary for the TRA to function. The TRA has its own internal
squelch/mute to block earpiece audio to the telephone.
Yellow TX Mod Audio Out (P1 Pin
8) Connect to modulator circuit. Use high impedance point in radio. Low-Z
will cause low frequency rolloff across tone output coupling cap C39 and
tone output resistor R59. In Low-Z mic circuits, it might be necessary to
short out resistor R59 with jumper JU6.
Dark Brown PTT Out (P1 Pin 7) Connect to the radio's PTT switch. The micro now has control of PTT,
time out timer, and busy lockout. The VOX controls the micro which
controls PTT output.
Violet
Scan (P1 Pin 2 Step or
Binary LSB) Connect to synthesizer push button channel stepper switch (select
desired channel scan type in
Decoding Parameters ). For binary,
connect to Least Significant Bit (first bit) on radio's binary address line.
White Binary Scan (P1 Pin 6
Binary Second Bit) Connect to second bit on radio's binary address line.
Blue Binary Scan (P1 Pin 12
Binary MSB) Connect to Most Significant Bit (third bit) on radio's binary address line.
Green
Horn (P1 Pin 4) Provides a 0-9 second momentary ground through FET transistor Q10.
RJ11 Connector (2 in
parallel) Plug in any standard single line phone or cordless phone. Phones can
be plugged into both of these and connected throughout the house in
rural phone applications. Note: The hybrid adjustment pot in the TRA
must be set to match the characteristics of a particular type of phone.