Midian Electronics TTC-1 User manual

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TTC-1
F1 to F16 Tone Remote Adaptor – Tone Termination Panel
Manual Revision: 2013-03-26
Covers Loader Firmware Revisions:
1.70 & Higher
Covers Application Firmware Revisions:
1.80 & Higher
Covers PCB Revisions:
E

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TABLE OF CONTENTS
Specifications 3
General Information 4
Hardware Installation 5
Hardware Alignment 8
Jumper Settings 10
Controls & Indicators 11
Operation 12
Product Programming 13
Tone Signaling Formats 16
TTC-1 Option A: Wildcard for Remote Monitoring & Control 17
Theory of Operation 18
Technical Notes 20
Contact Information 20

3
SPECIFICATIONS
Voltage/Current:
Operating Voltage: 13-18 VDC
Operating Current (standby): 125 mA
LED Current: 4 mA
Fuse Protection Auto Resettable with surge suppression: 300 mA
RX Input from Radio:
Compression Range: Not more than 3 db change for 30 db increase above threshold
Frequency Range: 300-3000 Hz
Notch Filter Depth: 45 db relative to 1 KHz
DTMF Decode Sinad Ratio 9 dB
Dynamic Range 30 dB
COR Input 0-5 V
TX Outputs to Radio:
Compression Range: Not more than 3 db change for 30 db increase above threshold
Notch Filter Depth: 45 db relative to 1 KHz
Output Impedance (TX): 600 Ohms or 22 K Ohms
Output Tone Level: 2/3 System deviation
Monitor: Open-Collector or Optional Relay
PTT Out: Open-Collector or Optional Relay
F1/F2: Open-Collector or Optional Relay
F3-F16: Open-Gate FET
Dedicated Phone Line:
Input Level +10 to -25 dB
Input Impedance 600 Ohm Balanced
Output Level -20 to 0 dB pot adjustable
Output Impedance 600 Ohm
Fuse Protection Auto Resettable with surge suppression: 300 mA
Mechanical:
Dimensions: 1.45" H x 6” W x 7.6" L
Operating Temp: 0° to +50° C
Default Control Tone Frequencies & Timing:
Function Tone Frequency Level & Duration Function
Tone Default Level & Duration
High-Level Guard 2175 Hz 10 dBm for 120 msec F8 1250 Hz 0 dBm for 40 msec
Low-Level Guard 2175 Hz -20 dBm continuous F9 1150 Hz 0 dBm for 40 msec
Monitor 2050 Hz 0 dBm for 40 msec F10 1050 Hz 0 dBm for 40 msec
F1 1950 Hz 0 dBm for 40 msec F11 950 Hz 0 dBm for 40 msec
F2 1850 Hz 0 dBm for 40 msec F12 850 Hz 0 dBm for 40 msec
F3 1750 Hz 0 dBm for 40 msec F13 750 Hz 0 dBm for 40 msec
F4 1650 Hz 0 dBm for 40 msec F14 650 Hz 0 dBm for 40 msec
F5 1550 Hz 0 dBm for 40 msec F15 550 Hz 0 dBm for 40 msec
F6 1450 Hz 0 dBm for 40 msec F16 2350 Hz 0 dBm for 40 msec
F7 1350 Hz 0 dBm for 40 msec

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GENERAL INFORMATION
Midian’s TTC-1 is a tone remote adaptor (tone termination panel) that supports F1-F16 function tones. The TTC-
1 uses EIA and Industry standards for monitor, guard, and F1-F16 function tones. Midian’s TTC-1 can also have
the F1-F16 function tones customized as well as the guard tones and monitor tone. In addition to these standard
features Midian’s TTC-1 offers voice prompts to provide a confirmation back to the dispatcher that an event, such
as a channel change, has occurred. Additionally the voice prompts can be programmed to go over the air for such
applications as emergency alerts.
The TTC-1 is available with several unique options. The remote monitoring and control option (TTC Option A)
offers 4 relay inputs/outputs and 4 opto-isolated inputs/outputs for monitoring and/or controlling equipment or
conditions. There are also options to have Midian’s TVS-2 rolling code scrambler (TTC Option G), Midian’s VS-
1200 frequency domain scrambler (TTC Option N) or Midian’s VPU-15 voice inversion scrambler (TTC Option H)
interfaced to the TTC-1. The standard configuration of the TTC-1 is for a 2-wire system. A 4-wire option (TTC
Option J) is available for these types of systems.
Midian’s TTC-1 can be used with Midian’s TRC series tone remote controllers or another manufacturer’s tone
remote controller that uses EIA and industry standard F1-F16 function tones.

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HARDWARE INSTALLATION
Be certain to follow standard anti-static procedures when handling any of Midian’s products.
Getting Started:
The TTC has a number of adjustment potentiometers and configuration jumpers. These have been adjusted and
configured at the factory for a typical installation. However, audio levels should be verified and adjusted (if
necessary) at the time of installation. Also, the configuration jumpers should be inspected prior to installation to
verify that they are in the right configuration. Jumper descriptions appear in the jumper settings section with a
quick reference table.
Line Interface
The line interface connector CON7 is a 10-pin RJ-45 style connector on the left side of the back panel.
2-Wire Operation: For a 2-wire installation, simply connect pins 5 and 6 (red and green) to the dedicated line.
This is the standard configuration for the TTC. See table 3.1.
Table 3.1
Pin Color 2-Wire
CON7-4 Black Not Used
CON7-5 Red Line 1
CON7-6 Green Line 1
CON7-7 Yellow Not Used
4-Wire Operation: For a single line 4-wire installation, connect pins 4 and 7 (black and yellow) for transmit audio
to the base station (Line In) and pins 5 and 6 (red and green) for receive audio from the base station (Line Out).
For this feature TTC Option J must be ordered and installed in the TTC-1. JP27 should be moved to the 2-3
position. See table 3.2.
Table 3.2
Pin Color 4-Wire
CON7-4 Black TX (Line In)
CON7-5 Red RX (Line Out)
CON7-6 Green RX (Line Out)
CON7-7 Yellow TX (Line In)
Diagram 3.1
1

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Radio Interface:
CON6 and CON2 are located in the middle of the back panel and are used to connect the TTC-1 to the base
station radio or repeater. The following are the connection points:
CON6:
CON6-1 (Gray): F2: Connect this lead to the F2 channel selector position on the radio. With JP14 installed in the
1-2 position, the output is an open-collector to ground. With JP14 installed in the 2-3 position, the optional F1/F2
relay is active low upon contact closure with JP15 installed in the 2-3 position.
CON6-2 (Orange): COR: Connect this lead to the busy detect of the radio. This input is used to control whether
audio should be passed down the line to the tone remote controllers. Generally this line is not used, but if the
base station has any low-level noise or hum this line will mute the noise until the radio opens squelch and passes
full audio. A logic low from the radio’s busy circuit will activate Q8.
CON6-3 (Violet): SPARE: Future Use.
CON6-4 (Yellow): Monitor: Connect this lead to the radio’s monitor input to disable CTCSS/DCS. With JP8
installed in the 2-3 position, the output is an open-collector to ground. With JP8 installed in the 1-2 position, the
optional monitor relay is active low upon contact closure with JP9 installed in the 2-3 position.
CON6-5 (Green): TX Output: Connect to the microphone input of the base station/repeater.
CON6-6 (Red): Battery (13-18 VDC): Connect this lead to 13-18 VDC from the base station/repeater.
CON6-7 (Black): Ground: Connect this lead to the base station’s or repeater’s ground.
CON6-8 (White): RX Input: Connect the receive audio in the base station after the sub-audible hi-pass filter and
at some point that gives flat audio to the TTC-1. Speaker audio is fine if it is single ended, but make certain the
volume control cannot be turned down accidentally.
CON6-9 (Blue): PTT Output: Connect this lead to the PTT on the radio. With JP1 installed in the 2-3 position, the
output is an open-collector to ground. With JP1 installed in the 1-2 position, the optional PTT relay is active low
upon contact closure with JP4 installed in the 2-3 position.
CON6-10 (Brown): F1: Connect this lead to the F1 channel selector position on the radio. With JP13 installed in
the 1-2 position, the output is an open-collector to ground. With JP13 installed in the 2-3 position and SJ-12
installed, the optional F1/F2 relay is active low upon contact closure with JP15 installed in the 2-3 position.

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CON2:
CON2-1 (Gray): RXD: Future Use.
CON2-2 (Orange): TXD: Future Use.
CON2-3 (Violet): F3 or Binary Select 1: This output is an open-drain FET than can pull the radio’s channel
select line to ground. This line can be used with CON2-4, CON2-5 and CON2-6 for multi-line (2, 3 or 4 line) binary
channel selection.
CON2-4 (Yellow): F4 or Binary Select 2: This output is an open-drain FET than can pull the radio’s channel
select line to ground. This line can be used with CON2-3, CON2-5 and CON2-6 for multi-line (2, 3 or 4 line) binary
channel selection.
CON2-5 (Green): F5 or Binary Select 3: This output is an open-drain FET than can pull the radio’s channel
select line to ground. This line can be used with CON2-3, CON2-4 and CON2-6 for multi-line (2, 3 or 4 line) binary
channel selection.
CON2-6 (Red): F6 or Binary Select 4: This output is an open-drain FET than can pull the radio’s channel select
line to ground. This line can be used with CON2-3, CON2-4 and CON2-5 for multi-line (2, 3 or 4 line) binary
channel selection.
CON2-7 (Black): F7: This output is an open-drain FET than can pull the radio’s channel select line to ground.
CON2-8 (White): F8: This output is an open-drain FET than can pull the radio’s channel select line to ground.
CON2-9 (Blue): F9: This output is an open-drain FET than can pull the radio’s channel select line to ground.
CON2-10 (Brown): F10: This output is an open-drain FET than can pull the radio’s channel select line to ground.

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HARDWARE ALIGNMENT
The alignments are preset at the factory and should not need to be adjusted during installation. However, if an
adjustment is needed please follow the procedures below.
TX Input Line Level Adjustment:
1. With the dedicated line connected to the TTC, connect a line level meter to the red and green (2-wire) or yellow and
black (4-wire option) in bridging mode.
2. Configure the line level meter to generate continuous low-level guard tone (2175 Hz at -20 dBm).
3. Adjust RP13 while monitoring TP10 with an oscilloscope, so that TP10 shows 1.2 V p-p. Also verify that JP-26 Pin 2
shows 220 mV p-p.
TX Notch Filter Alignment:
1. Continue generating the low-level guard tone from the line level meter in the previous step.
2. Monitor TP8 with a Sinadder. The audio level of the Sinadder should be adjusted to hear the tone.
3. Adjust RP9 until the tone is at it’s most diminished point.
4. Adjust RP10 until the tone fully diminishes. If this step does not get rid of the tone go to step 5.
5. Repeat steps 3 and 4 until no tone is heard.
TX Bandpass Filter Alignment:
1. Reconfigure the line level meter to generate a continuous low-level guard tone (2175 Hz at -20 dBm).
2. Adjust RP7 while monitoring TP6 with an oscilloscope, so that TP6 is peaked.
TX Mod Level Adjustment:
1. Reconfigure the line level meter to generate a continuous 1 KHz tone at -10 dBm.
2. With JP25 in the 1-2 position the output impedance is 22 K. For radios with a 600 Ohm impedance put JP25 in the
2-3 position.
3. Adjust RP8 for full system deviation.
RX Input Line Level Adjustment:
1. With voice being received from the base station adjust RP3 while monitoring TP1 with an oscilloscope, so that TP1
shows around 700 mV p-p. Also verify that JP-22 Pin 2 shows around 180 mV p-p.
RX Notch Bandpass Alignment:
1. Generate the low-level guard tone (2175 Hz at -20 dBm) using the line level meter to the RX Input from the radio.
2. Monitor TP2 with a Sinadder. The audio level of the Sinadder should be adjusted to hear the tone.
3. Adjust RP5 until the tone is at it’s most diminished point.
4. Adjust RP4 until the tone fully diminishes. If this step does not get rid of the tone go to step 5.
5. Repeat steps 3 and 4 until no tone is heard.

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RX Output Line Level Adjustment:
1. With voice being received from the base station adjust RP6 while monitoring the line out with a line level meter and
set for approximately -10 dBm on average voice or -5 dBm on peak voice.
Duplex Parallel Crossover Adjustment:
1. If the TTC is ordered with the 4-Wire Option it may be necessary or desirable for one tone remote controller to hear
another and to pass its keying tone to the other tone remote(s) to activate the busy light. If so, set RP15 for a level
adequate to activate the busy indication on the other tone remote(s) and to a level that is comfortable.

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JUMPER SETTINGS
The following table shows the default jumper settings and their function:
Jumper
Number Default Position Description
JP1 1-2 Out – 2-3 In PTT open collector transistor output or relay selection
JP4 1-2 Out – 2-3 In Active low versus active high selection for PTT Relay
JP8 1-2 Out – 2-3 In Monitor open collector transistor output or relay selection
JP9 1-2 Out – 2-3 In Active low versus active high selection for Monitor Relay
JP13 1-2 In – 2-3 Out F1 open collector transistor output selection
JP14 1-2 In – 2-3 Out F2 open collector transistor output or F1/F2 relay selection
JP15 1-2 Out – 2-3 In Active low versus active high selection for F1/F2 Relay
JP20 1-2 In – 2-3 Out Active low versus active high selection for COR Input
JP22 1-2 Out – 2-3 In AGC Compander Circuit bypass
JP25 1-2 In – 2-3 Out 22K versus 600 Ohm impedance selection
JP26 1-2 Out – 2-3 In AGC Compander Circuit bypass
JP27 1-2 In – 2-3 Out 4-Wire Option
JP36 1-2 In Termination jumper
JP37 1-2 In Termination jumper
JP38 1-2 In Termination jumper
JP40 1-2 In Termination jumper
JP41 NA Not used
JP42 NA Not used
JP43 NA Not Used
JP44 NA Not Used
JP45 1-2 In – 2-3 Out Not Used
Jumper
Number Default Position Description
SJ1 1-2 Out – 2-3 Out Future Use
SJ2 1-2 Out – 2-3 Out Future Use
SJ3 In Future Use
SJ4 In Future Use
SJ5 In Future Use
SJ6 In Future Use
SJ7 In Future Use
SJ8 In Future Use
SJ9 In Future Use
SJ10 In Future Use
SJ11 In Future Use
SJ12 Out F1/F2 Relay use instead of the open collector output
SJ13 In Remove for voice scrambler only
SJ14 In Remove for voice scrambler only
SJ15 Out De-Emphasis jumper

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CONTROLS & INDICATORS
Power Switch: This is a single pole toggle switch on the front left of the TTC-1. The down position is off and the
up position is on.
Power LED: This red LED indicates that power is applied to the unit and that the switch is on.
Transmit LED: This red LED indicates that the unit is applying push to talk to the base station or repeater.
DTMF LED: Not used.
Carrier LED: This red LED indicates when a monitor output is turning off the CTCSS/DCS and monitoring the
standard carrier squelch or that carrier is detected on the base station radio.
Tone/Sync LED: This red LED indicates presence of low-level guard tone or that optional scrambler sync is being
decoded.
Ring LED: Not used.
Hook LED: Not used.
F1-F10 LEDs: On the TTC-1 the F1/F2 LEDs are shown on the front panel. The F3-F10 LEDs are inside and are
visible with the lid removed for testing purposes. These LEDs show the currently selected function tone. When
programmed to binary 1-16 or 0-15 the F3, F4, F5 and F6 LED’s display in binary with F3 being the LSB and F6
being the MSB.

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OPERATION
Channel Change: Depending on how the TTC is set up, upon receiving a function tone F1-F16 the TTC will give
an open collector output to ground (discreet or binary) to cause the base station radio to change to the desired
radio channel.
Transmit: Upon receiving the low-level guard tone the TTC will PTT the radio (CON6-9) by giving an open
collector or relay output to ground, causing the base station radio to key. The voice will be transmitted to the radio
via CON6-5.
Monitor: Upon receiving the 2050 Hz Monitor tone from the tone remote controller, the TTC will give a
momentary or latched open collector or relay output to ground via CON6-4 to the base station radio.
Receive: Upon receiving audio/signaling from the base station radio the TTC will pass the audio/signaling to the
line output to the tone remote controller.

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PRODUCT PROGRAMMING
Midian will preprogram the TTC-1 for any of the following configurations prior to shipping at no charge:
F1/F2: Open collector outputs to ground for F1 and F2 select. This configuration also provides for F3-F10
selection.
F1/F2 Relay Output: Active high contact closure for F1 and active low contact closure for F2.
2-Line Binary: This uses the F3 and F4 lines as the 2-Line Binary control with an active low polarity for F1-F4
channel selection.
3-Line Binary: This uses the F3, F4 and F5 lines as the 3-Line Binary control with an active low polarity for F1-F8
channel selection.
4-Line Binary: This uses the F3, F4, F5 and F6 lines as the 4-Line Binary control with an active low polarity for
F1-F16 channel selection.
The KL-4F and KL-4F-PC1 must be purchased if using a configuration other than above or when using the TTC
Options A, G and/or H.
At any time while programming the TTC-1, right clicking on an option will bring up a help file to explain the
parameter.
The KL-4F and KL-4F-PC1 plug into the 3.5 mm stereo plug on the front of the TTC-1.
Set the parameters of the TTC-1 to fit the application. Turn on power to the TTC-1 and send the program to the
unit.
After programming cycle power to the TTC-1 and remove the KL-4F and KL-4F-PC1.
The majority of users would only need to change parameters of the General Parameters tab in the MPS
programming software. These parameters are explained on the next two pages. For an explanation of the other
tabs, please use the help files in the software.

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High Level Guard Tone Duration: This field is programmable from 0.05 to 9.99 seconds in 10 millisecond
increments. This sets the length of the high level 2175 Hz guard tone. 120 milliseconds is the EIA standard time.
Freq/Func Tone Duration: This sets the length of the frequency/function tone. 40 milliseconds is the EIA
standard time.
Key-Up Delay: This field is programmable for 0.0 to 9.9 seconds in 100 millisecond increments. This sets the
time in seconds the unit gives a PTT to the radio and then generates any voice prompts or CWID tones.
COR Settings > COR Enable: If checked, the unit will monitor the COR input to determine if the incoming receive
audio path should be allowed to send incoming audio from the radio to the tone remote controller or if it should
stay quieted.
COR Settings > Polarity: Select Low or High to match the active COR polarity of the base station.
Deactivate Monitor on PTT: If checked, the unit will place the monitor output in a non-active state when
receiving a PTT command from the tone remote controller.
Only One Output On at a Time: This field only applies when using the outputs to control functionality other than
channel selection on the base station radio. This could include turning other equipment on/off.

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F1/F2 Relay Enable: If using the optional relays instead of the open collector transistor outputs, check this box.
When the relay is energized the unit has F2 selected and when relaxed F1 is selected.
High Level Guard Clamp: If checked, upon detection of a high-level guard tone being broadcast by the tone
remote control, the unit will forcibly mute the incoming receive audio from the base station radio. If this feature is
not checked and the incoming receive audio from the base station is noisy, the incoming audio may overpower
the guard tones and function tones from the tone remote controller, so that remote control of the unit may not be
possible.
4-Wire Mode: If the unit is ordered with the 4-wire option, this box must be checked.
Remote Control Access Code: The frequency/function tones can be controlled using DTMF from a two-way
radio on the system with a DTMF keypad. This specifies the 4-digit DTMF code to access these functions.
Remote Control Inactivity Delay: After the Remote Control Access code has been successfully entered, this
time specifies the amount of time upon not receiving any DTMF tones, voice or COR that the unit will cancel the
remote access.
Number of Binary Outputs: If set for disabled, the F1-F10 are discreet outputs. If set for 2 outputs, then the F3
and F4 output wires are used for 2-line binary channel selection (F1-F4). If set for 3 outputs, then the F3, F4 and
F5 output wires are used for 3-line binary channel selection (F1-F8). If set for 4 outputs, then the F3, F4, F5 and
F6 output wires are used for 4-line binary channel selection (F1-F16). The table below shows the active (A) and
inactive (I) states for the binary output wires (top) to get the desired function tone (side).
2-Line Binary Outputs 3-Line Binary Outputs 4-Line Binary Outputs
CON2-3 CON2-4 CON2-3 CON2-4 CON2-5 CON2-3 CON2-4 CON2-5 CON2-6
F1 A I A I I A I I I
F2 I A I A I I A I I
F3 A A A A I A A I I
F4 I I I I A I I A I
F5 A I A A I A I
F6 I A A I A A I
F7 A A A A A A I
F8 I I I I I I A
F9 A I I A
F10 I A I A
F11 A A I A
F12 I I A A
F13 A I A A
F14 I A A A
F15 A A A A
F16 I I I I
Active Polarity: Select whether a High or a Low will be the active state of the binary outputs.
Offset By One: This checkbox allows for the compensation of an attached radio that uses Binary 0 as Channel 1.
If checked, the function tone ID is reduced by one to product the Binary 0 ID. For example, if Function Tone 1 is
sent to select radio channel 1 and the radio uses a binary code of 0 to select channel 1, this checkbox would need
to be checked for the correct binary code to be generated for that particular radio.
CWID Delay: This field is programmable for 0-60 minutes in one minute increments. If set to 0, this feature is
disabled. This sets the time in minutes to automatically identify the transmitting station. If enabled, after
approximately 15 seconds have elapsed of no activity and the delay timer has expired, the CWID for this unit will
be transmitted and the delay timer will be restarted.
CWID Message: Select whether you want a Text CWID (Morse Code) or a voice message CWID (Audio). If you
will not use the CWID, select None. Type the text of the CWID you would like transmitted in the box below this
field or select the voice clip from the drop down box two boxes below this field.

16
TONE SIGNALING FORMATS
Signaling Format Compatibility
In tone remote systems, the industry standard 2175 guard tone is filtered out by the tone remote adapter at the
base station so that it is not heard over the air. This filter can affect some 5-Tone and 2-Tone signaling formats
close to 2175 Hz. Tones within +/-70 Hz could be attenuated to a level such that they cannot be decoded by
receiving equipment. There are several ways to deal with this issue:
1. Choose a format that will not be affected.
2. Do not use the affected tone(s).
3. Change the guard tone.
The last solution involves re-tuning the notch filters on the TTC. This can be done at the factory upon request
(recommended). It also requires that the guard tone and notch filters on the tone remote controller be changed as
well. While Midian’s products allow for this, not all do. Please note that this issue often applies to decoding as
well. Tone remote controllers notch 2175 out of the receive audio as well. This possibility should be investigated if
decode problems are experienced. The following sections address the formats and tones that are likely to be
affected.
ZVEI: All ZVEI formats use 2200 Hz for either the ‘0’ or the ‘9’ tone. This is only 25 Hz away from the standard
guard tone frequency of 2175. The best solution to this problem is to simply not use the ‘0’ tone when encoding
DZVEI and not use the ‘9’ tone when encoding ZVEI or DDZVEI formats. Alternatively, the guard tone could be
changed to another frequency. If this is done, it should be at least 150 Hz away from the nearest frequency used
by the format. 2970 Hz is a common choice.
CCIR and EEA: CCIR and EEA both use the tone 2110 Hz as the ‘repeat’ tone. This tone indicates that the
current digit is the same number as the last digit. The best solution to this problem is to simply not use codes that
have repeating digits. That is to say, do not use a code where a digit appears next to itself in the code such as
‘12334’ which has two 3’s in a row. Another solution is to change the guard tone. If this is done, it should be at
least 150 Hz away from the nearest frequency used by the format. 2970 Hz is a common choice.
Other Affected Formats: REACH two-tone, tone group A, uses 2196 and 2121 Hz to represent the digits 7 and
8. Do not use tone group A if using this format. PLECTRON tones 2260 and 2164 should not be used.
Formats Not Affected: The following formats do not use tones between 2105 and 2245 and therefore should be
unaffected by the guard tone filter: AVCALL, DTMF, EIA, EUROSIGNAL, GE Type 99, MODAT, NATEL, Motorola
Quick Call I, and Motorola Quick Call II.

17
TTC-1 OPTION A: WILDCARD
The TTC-1 Option A enables the dispatcher to send function tones to remotely monitor and control up to 4 opto-
isolated inputs and 4 relay outputs. The relays are Dual Form C rated for 0.3 Amp at 125 VAC, 0.3 Amp at
110VDC or 1 Amp at 30 VDC.
The 4 relay outputs are controlled by the function tones F11 to F14. Upon receipt of the corresponding function
tone, the output can be latched or momentary with the TTC-1 generating a voice clip to indicate the action (i.e.
“generator on”, “generator off”).
The TTC-1 can be programmed to send voice prompts for the active and inactive states of the 4 opto-isolated
inputs (i.e. “door open”, “door closed”). This is ideal for monitoring lighting systems, back-up power systems and
intrusion.
Hardware Connections:
Connection to TTC-1: Plug one side of the supplied RJ cable into CON3 on the TTC Option A and plug the other
side into CON3 on the TTC-1.
Relay Outputs: The relay outputs are Dual Form C rated for 0.3 Amps at 120 VAC and offer a normally open and
a normally closed set of contacts, as well as a center common point to connect to a common ground. These
outputs can be used to activate equipment such as generators, pumps, etc.
Opto-Isolated Inputs: These 4 bi-directional LED inputs are used to alert the dispatcher of an event. For
instance if a tower light goes out or an intrusion alarm is activated. These auxiliary inputs can be programmed as
active high or active low in the programming of the TTC-1.
Note: Each of the 4 opto-isolators use bi-directional LED’s so these can be used on AC or DC. When using the
opto-isolator for sensing low voltage DC keep the 10 K and 100K resistors installed. When using to sense 120
VAC remove the 10 K resistor so only the 100 K remains to provide current limiting for the opto diodes.

18
THEORY OF OPERATION
TX Voice Path:
Phone line audio from the tone remote controller is fed into the TX voice path in simplex mode through
transformer T1. In 4-wire mode it is fed into transformer T2 and is selected by jumper JP27. Both transformer
circuits have surge suppression and an auto-resettable polyswitch for lightning protection. They each have RF
chokes and RF bypass caps to keep out any RF that may get into the phone lines. For best results an extra Earth
ground connection is provided at J1.
Audio is input through Pin 2 of JP27 through a hi-pass filter C123 and RP13 to block any 60-cycle hum from an
unbalanced phone line. Audio is then passed into TX amp low pass filter U14:3. The low pass filter rolls off noise
above 3 KHz. It’s output is about 1.2 V p-p with -20 dBm with low-level guard tone on the phone line. The output
of this amp passes through compression amp circuit U14:4 and U7:2. Its output is about 155 mV p.p. This is the
threshold of compression. Jumper JP26 allows you to select the compressed audio or non-compressed audio.
When using short phone lines with stable levels you may choose to use the non-compressed audio as the audio
coming from the tone remote controller is already compressed. Several competing units do no employ the
compression circuit.
Pin 2 of JP26 is the input into a bi-quadratic filter U15:2, U15:1, and U15:4. The band pass output is on Pin 7 and
can be peaked using frequency tuning pot RP9. The frequency tuning 25-turn pot RP9 will tune over a range of 1
KHz from 2100 to 3100 Hz. The band pass output on Pin 7 is fed into notch null pot RP10 along with the voice
and Guard Tone through R179 into RP10. The two Guard Tone frequencies are 180 degrees out of phase and
cancel at the input of U15:3. From U15:3’s output the remaining voice is fed into C89 where an optional voice
scrambler may be installed. From the other side of C89 it is passed into mixer U14:2 and then output through a
high Z or low Z circuit to the base station’s modulator. This amplifier is also a mixer for the pulse width modulator
encoder.
RX Voice Path:
RX audio from the base station goes through hipass filter C39 and RP3. RP3 also serves as the RX input level
adjustment pot. This audio is then fed into amplifier U8:2 which acts as low pass filter for noise above 3 KHz and
if jumper SJ15 is installed it can give a 6 dB per octave de-emphasis if desired.
Audio from U8:2 is fed into the compression amplifier U7:1 and U14:1 or it can be bypassed around the
compressor using JP22. From JP22 it goes to C56 where an optional voice scrambler may be installed. From
there it passes through the notch filter to remove 2175 Hz voice components. This circuit works in exactly the
same way as the description for the TX Voice Path. Voice audio from the notch filter is input into the audio mixer
U18:4. This mixer also receives duplex crossover audio and MSK encoded audio. Out of the mixer they are then
input into the line amplifier (U20:1) which drives T1. The line amplifier has an enable transistor that is controlled
by the microprocessor. The micro can respond to the COR carrier input and enable this amplifier if necessary or
desirable via programming.
Signaling Path:
Signaling audio from T1 or T2 passes through the TX amp U14:3. Tone remote audio from input level pot RP13 is
fed into the Guard Tone state variable band pass filter and into the broadband function tone detector circuit via
U10:3. The Guard Tone frequency is normally 2175 Hz, and the high Q state variable filter has a 6 dB bandwidth
of about + or – 70 Hz. It is then fed into the Guard Tone detector U11:3 and Schmitt Trigger U10:1 and level
shifter Q23 to the microprocessor for frequency validation. Once it has been validated and checked for the proper
timing, the microprocessor then looks at the function tone output from Q22 and performs the monitor or frequency
function following the high-level Guard Tone command. U10:2 is a high gain amp for the function tone followed by
Schmidt trigger U10:4.

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Power Supply:
13-18 VDC is input on the red wire of the Radio Interface connector and then into S1 the ON/OFF switch through
RF inductor L7 into a resettable polyswitch. D22 is a polarity protection diode that is designed to pop the
resettable fuse if power is hooked up backwards. C31 and C34 act as RF bypass caps after the RF inductor L7.
U6 acts as a 12 VDC regulator. Its output is fed to all of the analog circuitry and U14:2 acts a pseudo-ground
reference at approximately 6 VDC. The 12 VDC on the analog page schematic is also fed over to U4 which is a 5
VDC regulator shown on the digital page to run the microprocessor and the optional encoders/decodes and serial
chips. The relays on the digital page receive their 12 VDC from the 12 VDC regulator. They are driven by open-
collector transistors to protect the microprocessor from the 12 VDC.
Microprocessor Schematic:
The microprocessor utilizes a 16 MHz clock and is a flashable part. It communicates with the optional DTMF
encoder decoder U1. This encoder/decoder is designed with future options whereby the dispatcher could control
hundreds of channels or trunk groups as opposed to the discreet or binary channel selection. These will be
developed over time for different manufacturers and their particular protocols.
The microprocessor has an optional I/O relay interface for F11-F14. This interface has optical isolators and relays
to interface to higher voltages for performing remote control output functions and alarm inputs.
On the right hand side of the microprocessor page we have all of the LED functions shown. See the Control and
Indicators section.
The F3-F10 outputs are open-drain FET switches that simply pull to ground to provide a logic low or provide
ground to energize a relay. F3, F4, F5 and F6 act as binary lines and the associated LED’s indicate the binary
selection. When using binary F1-F16 the F17 function controls the scrambler (if installed). F17 is actually the F2.
The F1 and F2 outputs are not used for binary.
There are 3 optional relays for PTT, Monitor, and F1/F2. Otherwise the outputs are open-collector to ground.
The microprocessor also has its own serial output. This serial output can talk to the RS232 chip for optional serial
interfaces. These are also designed to work with the previously mentioned DTMF encoder/decoder for frequency
and group control of various manufacturers control protocols.
This product includes a pulse width modulator output from the microprocessor that is fed into emitter follower Q3
and output on level pot RP2. This is fed into the TX and RX audio paths for transmitting pre-canned voice
messages, channel changes, evacuation, or other warning tones. The messages can be created with our KL3
software and a computer using a Microsoft Windows compatible sound card and a microphone. The messages
may be activated by programming the microprocessor to use the F1-F17 function commands.

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TECHNICAL NOTES
No technical notes are available at this time.
MIDIAN CONTACT INFORMATION
MIDIAN ELECTRONICS, INC.
2302 East 22nd Street
Tucson, Arizona 85713 USA
Toll-Free: 1-800-MIDIANS
Main: 520-884-7981
E-mail: [e-mail]
Web: www.midians.com