P
AGE
4
M
IDIAN
E
LECTRONICS
I
NCORPORATED
DDU-100/200
Manual
2 OVERVIEW
The DDU provides the optimal ANI display decoder
solution for small and medium sized radio systems
such as those used by taxi fleets, police departments,
construction crews, etc. It offers many features
normally found only in large and expensive Computer
Aided Dispatch (CAD) systems in one compact
desktop unit.
It can encode and decode most popular tone signaling
formats. The last 10 ANI's received can be reviewed at
any time. It can store up to 137 aliases in its user
database. The user friendly menu system makes it as
easy to use as a cell phone. Additional features include
status display and the ability to automatically mute
incoming leading ANI's
3 INSTALLATION
INSTRUCTIONS
Installation Note:
Midian products utilize CMOS integrated
circuits, which are susceptible to damage from high static
charges. Be sure to follow standard antistatic procedures
when handling, including using grounded workstations and
soldering irons and wearing grounding bracelets.
3.1 R
ADIO
I
NTERFACE
Radio Interface connector P1 is an 8-pin
RJ-45 style connector in the center of the
back panel.
+V IN (P1-5) [Red]
The DDU can be powered either by an optional wall
transformer or by the radio power supply. Connect this
wire to the radio power source provided it is between
12 and 15 VDC.
If using a wall transformer, make sure the voltage is
between 12 and 15 VDC and the current rating is at
least 800mA. Also, be certain that positive is
connected to the inside ring.
GROUND (P1-6) [Black]
Connect to radio ground.
AUDIO INPUT/RX IN (P1-8) [Blue]
Connect to a point in the radio where receive audio is
present at a constant level. If using PL or CTCSS, be
sure to connect to a point after the CTCSS high pass
filter. If using the Squelch Output of the DDU, be sure
the RX audio point is not muted when the radio is
squelched.
AUDIO OUTPUT/TX OUT (P1-4) [Green]
Connect to the mic-hi input of the radio. The output
impedance of the DDU can be adjusted if necessary by
replacing leaded resistor R81 with an appropriate
value.
PTT OUTPUT (P1-3) [Yellow]
This open collector output provides a ground to key-up
the radio when transmitting. If connecting to a relay in
the radio, make sure the coil is bypassed with a diode
to eliminate counter-EMF.
This output may also be assigned to be the repeater
access control output. See
REPEATER SETUP
for
more information.
COR INPUT (P1-1) [Gray]
Connect to a point in the radio squelch or CTCSS
circuit that changes logic level when carrier (or
CTCSS) is detected. A radio whose circuitry provides a
logic-low or logic-high can readily turn Q1 on and off. If
only a high level is provided, it may be necessary to
move R40 from its pull-up to its pull-down position.
Note that it is required that the COR Input be in the
active state in order to decode all formats except
DTMF. If COR is not to be connected, make sure it is
programmed to be active HIGH. A COR connection is
required in order to use busy lockout, auto ANI mute,
and repeater access control features.
MONITOR OUTPUT (P1-7) [Orange]
This output can be used to control the monitor function
of the radio using the <MONITOR> button on the DDU.
This is an open collector output which changes state
each time the <MONITOR> button is pressed.
This output may also be assigned to be the repeater
access control output. See
REPEATER SETUP
for
more information.
SQ OUT/LTR IN (P1-2) [Brown]
This wire may be either a
Squelch Output
or a
Trunking Delay
(LTR) input, but not both. To use as a
squelch output, install jumper R85 and make sure
jumper JU5 is not installed. To use as a trunking delay
input, remove R85 and install JU5.
When used as a Squelch Output, connect to a point in
the radio which will mute the speaker when brought to
ground (or left floating). Program the appropriate
polarity in the
RADIO SETUP
menu.
When used as an LTR Trunking Delay Input, connect
to a point in the radio which changes state between 0
and 5 VDC when a channel has been acquired on the
LTR trunking system. The active (channel acquired)
state of this input is programmable in the
RADIO
SETUP
menu.
