Midian Electronics TRC-1 User manual

1
TRC-1
Tone Remote Controller with DTMF Dialing
Manual Revision: 2012-07-27
Covers TRC Firmware Revisions:
1.22 & Higher
Covers Keyboard Firmware Revisions:
3.2 & Higher
Covers Encoder/Decoder Firmware Revisions:
1.7 & Higher
Covers PCB Revisions:
G & Higher

2
TABLE OF CONTENTS
Specifications 3
General Information 4
Hardware Installation 5
Hardware Alignment 7
Jumper Settings 9
Controls & Indicators 10
Operation 12
Product Programming 13
TRC Option H: Multi-Format Dialing 15
Theory of Operation 18
Technical Notes 20
Contact Information 20

3
SPECIFICATIONS
Voltage/Current:
Operating Voltage: 18 VDC
Operating Current (standby): 170 mA
Operating Current (RX): 310 mA
Operating Current (TX): 170 mA
RX Inputs:
Input Impedance (RX): 600 Ohms
Compression Threshold: Adjustable to –20 dbm
Compression Range: Not more than 3 db change for 30 db increase above threshold
Speaker Audio Output: 2.0 Watt
Distortion: Less than 3% at full audio
Hum & Noise: 50 db below normal operating level
Frequency Response: Less than 3 db from 300 Hz-3 KHz
Notch Filter Depth: 45 db relative to 1 KHz below compression
TX Outputs:
TX Output: Adjustable to +15 dbm on 2175 Hz
Output Impedance (TX): 600 Ohms
Mic Compression Threshold: Adjustable typically 50 mv
Compression Range: Not more than 3 db change for 30 db increase above threshold
Hum & Noise: 50 db below normal operating level
Notch Filter Depth: 45 db relative to 1 KHz below compression
Mechanical:
Dimensions: 2.875" H x 6.5” W x 8.75" L
Operating Temp (excluding LCD): -30° to +60° 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 F17 2450 Hz 0 dBm for 40 msec
Encode Formats:
DTMF (0-9, *, #)

4
GENERAL INFORMATION
Midian’s TRC-1 is a basic tone remote controller with DTMF dialing. The TRC uses EIA and Industry standards
for monitor, guard, and F1-F16 function tones. Midian also adds F17 for additional function control when used
with Midian’s TTC-1. The TRC comes standard with an internal microphone and speaker. A gooseneck
microphone (TRC Option A) or handset and cradle (TRC Option C) are also available. The standard configuration
is for a 2-wire and single line system. A 4-wire option (TRC Option F) or a Line 2 option (TRC Option E) is
available for these types of systems. An LCD option (TRC Option I) is available for displaying frequency/function
selection, time and dialing sequences.
Midian’s TRC can be used with Midian’s TTC-1, tone remote adaptor, or another manufacturer’s tone remote
adaptor that uses EIA and industry standard F1-F16 function tones.

5
HARDWARE INSTALLATION
Be certain to follow standard anti-static procedures when handling any of Midian’s products.
Getting Started:
The TRC 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. NOTE: The Zener Diode D-605 is installed to reduce the input voltage to regulators U601
and U602. D-605 is operating within specifications however when the TRC is open for adjustment, care should be
used to avoid touching the diode as it can be hot to the touch.
Line Interface
The line interface connector PL1 is a 10-pin RJ-45 style connector in the center of the back panel. A standard 4-
pin RJ-11 cable will plug into the RJ-45 and connect to the center 4-pins that are needed for 2-wire or 4-wire
interfaces. The remaining 6 pins are for use with a telemetry radio or microwave E&M options and for future
interoperability options.
2-Wire & Line 1 Operation: For a single line, 2-wire installation, simply connect pins 5 and 6 (red and green) to
the dedicated line. This is the standard configuration for the TRC. See table 3.1.
Table 3.1
Pin Color 2-Wire
PL1-4 Black Not Used
PL1-5 Red Line 1
PL1-6 Green Line 1
PL1-7 Yellow Not Used
2-Wire with Line 1 & 2 Operation: For a 2-line, 2-wire installation connect pins 5 and 6 (red and green) for line 1
and pins 4 and 7 (black and yellow) for line 2. For this feature TRC Option E must be installed in the TRC.
Remove JP202 and JP203 for proper operation. See table 3.2. Please note that the 4-Wire Option (TRC Option
F) is not available in Line 2 operation.
Table 3.2
Pin Color 2-Wire
PL1-4 Black Line 2
PL1-5 Red Line 1
PL1-6 Green Line 1
PL1-7 Yellow Line 2
Diagram 3.1
1

6
4-Wire & Line 1 Operation: For a single line 4-wire installation, connect pins 4 and 7 (black and yellow) for
receive audio and pins 5 and 6 (red and green) for transmit audio. For this feature TRC Option F must be installed
in the TRC. JP204 should be moved to the 3-4 position. See table 3.3. Please note that the Line 2/Supervisor
Option (TRC Option E) is not available in 4-wire operation.
Table 3.3
Pin Color 4-Wire
PL1-4 Black RX
PL1-5 Red TX
PL1-6 Green TX
PL1-7 Yellow RX
Parallel Remote Operation: When multiple remotes are connected to a single dedicate phone line JP304 must
be installed in the unit furthest from the phone line connection. All remaining units must have JP304 removed.
Diagram 3.2 – Parallel Remote Wiring
Supervisor Operation: When using the supervisor option (TRC Option E), the supervisor TRC is connected to
the line via pins 2 and 3. The remaining TRC’s pins 5 and 6 are connected in parallel to the supervisor’s TRC pins
4 and 7. To enable these remotes, the supervisor relay must be engaged by pressing the * and # keys
simultaneously.
Diagram 3.3 – Supervisor Wiring
Telemetry Radio: Rather than connecting the TRC to a dedicated line to communicate with the tone remote
adaptor, telemetry radios can be used for communication. If connecting to a telemetry radio connect PL1 as
follows to the radio:
PL1-3: PTT Output: Connect to the PTT of the radio. Jumpers JP210 1-2 and JP208 1-2 should be installed.
PL1-6: TX Audio Output: Connect to the mic-hi input of the radio. Install JP205 2-3.
PL1-7: RX Audio Input: Connect to a point in the radio providing flat receive audio. Install JP11 1-2 & remove
JP204.
PL1-9: Battery: 15 volts through a 100 Ohm current limiting resistor (R216).
PL1-10: Ground: Connect to the ground of the radio.
Microwave: Connect the 4-wire audio to the TX and RX sides of the microwave. If the M lead is desired install
JP208 1-2 and JP10 1-2. Connect the microwave’s M lead to PL1 Pin 3 for an open collector to ground. If using
an external relay to control the microwave’s M lead you may use Q205 to provide 12 volts and install JP207 1-2
and JP208 2-3.
PL1-8: External Speaker or PA System
5
TRC
65
TRC
6 5
TRC
6
To Tone
Remote
Adaptor
JP304
Out JP304 Out JP304 In
To Tone
Remote
Adaptor 66
7
4
5
TRC
5 TRC
6 5
TRC
Supervisor

7
HARDWARE ALIGNMENT
The following procedures assume a good quality dedicated line is being used and the tone remote adaptor is already
installed. 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.
RX Input Line Level Adjustment:
1. With the dedicated line connected to the TRC, connect a line level meter to the red and green (or yellow & black
with the 4-wire option) in bridging mode. If testing on a bench with no tone remote adaptor available use termination
mode on the line level meter.
2. With the line level meter generating Low-Level Guard Tone at -20 dBm, monitor TP304 with an oscilloscope.
3. Adjust RP306, so that 200 mV p-p is seen at TP304 or 165 mV p-p is seen at TP301. If paralleling multiple remotes,
this alignment should be done with all remotes attached.
TX Output Line Level Adjustment:
1. With the dedicated line connected to the TRC, connect a line level meter to the red and green in bridging mode. If
testing on a bench with no tone remote adaptor available use termination mode on the line level meter.
2. Set RP201 to 90%.
3. Push and hold the SEND key on the TRC to generate the Low-Level Guard Tone.
4. Adjust RP202 so that the line level meter shows the Low-Level Guard Tone at -20 dBm. If paralleling multiple
remotes, this alignment should be done with all remotes attached.
RX Notch Filter Alignment:
1. Generate the 2175 Hz Low-Level Guard Tone to the TRC.
2. Turn RP303 fully clockwise.
3. Monitor TP303 with a Sinadder. The sensitivity of the Sinadder should be adjusted to hear the tone.
4. Adjust RP302 until the tone is at it’s most diminished point.
5. Adjust RP303 until the tone fully diminishes.
6. Repeat steps 4 and 5 until no tone remains.
TX Notch Filter Alignment:
1. Unplug the internal microphone from the TRC, install JP101 1-2 and turn RP102 fully clockwise.
2. Push and hold the SEND key on the TRC to generate the 2175 Hz Low-Level Guard Tone.
3. Monitor TP103 with a Sinadder. The sensitivity of the Sinadder should be adjusted to hear the tone.
4. Adjust RP103 until the tone is at it’s most diminished point.
5. Adjust RP102 until the tone fully diminishes.
6. Repeat steps 4 and 5 until no tone remains.
7. After aligning the TX notch filter, remove JP101 and plug back in the internal or gooseneck microphone.
Handset Ear Level (TRC Option C Only):
1. With a field radio talking on channel to the TRC, adjust RP304 to a comfortable level.

8
JUMPER SETTINGS
The following table shows the default jumper settings and their function:
Jumper
Number Default Position Description
JP101 Out Install during TX Notch Filter Alignment only
JP201 Out Sidetone for dialing (4-wire option only)
JP202 In Removed when TRC Option E is installed (Line 2/Supervisor)
JP203 In Removed when TRC Option E is installed (Line 2/Supervisor)
JP204 1-2 In – 3-4 Out 2-wire (1-2 In 3-4 Out) or 4-wire option (1-2 Out 3-4 In)
JP205 1-2 In – 2-3 Out Balanced (1-2 In 2-3 Out)/Unbalanced (1-2 Out 2-3 In) Audio
Selection for use with a telemetry radio instead of a dedicated line.
JP206 Out Power with current limit.
JP207 Out Activates Q205 to provide 14 V to external M lead relay.
JP208 Out If JP208 1-2 is installed with JP210 1-2, provides an open-collector
to ground on PL1-3 to PTT a telemetry radio or ground a relay for
an M lead.
JP209 In Always installed unless directed otherwise by Midian.
JP210 1-2 Out – 2-3 Out Install JP210 1-2 with JP208 1-2 to PTT a telemetry radio.
JP301 1-2 In – 2-3 Out Future Use
JP302 Out Handset Audio Feedback. Install only with the TRC Option C if dial
tones and voice in the ear piece are desired.
JP303 Out TX Audio Loading. If less TX audio is needed, install this jumper.
JP304 In 2-Wire RX Audio Termination. If more RX audio is needed, remove
this jumper. This should only be needed if paralleling remotes.
JP305 Out 4-wire option only. RX Audio Loading. If less RX audio is needed,
install this jumper.
JP306 Out 4-wire option only. RX Audio Termination. If more RX audio is
needed, remove this jumper. This should only be needed if
paralleling remotes.
JP307 1-2 Out – 2-3 In With 2-3 installed the volume control switch is the main source of
controlling the handset ear piece audio level. With 1-2 installed and
2-3 removed, the volume control switch does not affect the handset
ear piece audio level and RP304 is the only source of control.
JP308 Out Low impedance audio for external speaker or PA System.
JP309 In Leave In: In for hard mute and out for soft mute
JP401 Out Factory Use Only
JP409 Out Factory Use Only

9
CONTROLS & INDICATORS
Power/Volume Switch: On the right side of the TRC, there is a switch which acts as the power and volume
switch. The switch is in the power off position when turned fully clockwise past the click. Turning the switch
counter-clockwise past the click turns the power on to the volume control. At this point the volume is in the low
position. Turning the switch further counter-clockwise increases the volume.
LCD: The 2-line LCD (TRC Option I) displays the time on the first line and the frequency selection and function
selection on the second. When a dialing sequence is performed the second line is cleared and the dialing
sequence is displayed.
LED 1 (PWR - LINE/SUP): This LED is a bi-color LED. The LED will glow red when the power is on to the TRC. It
glows orange when Line 2/Supervisor mode is active.
LED 2 (SEND - F1/F2): This LED is a tri-color LED. The LED will glow red during transmit of Freq 1 and orange
during transmit of Freq 2. It glows green when Guard Tone is detected from a parallel tone remote.
FREQ: The FREQ button acts as the frequency select and the function select key. Pressing this key followed by
0-17 will select the associated frequency or function. When using the TRC with Midian’s TTC series tone remote
adaptor both frequency and function tones are available. When using the TRC with another manufacturer’s tone
remote adaptor the frequency tones are selectable.
INTER: Pressing the INTER key will allow intercom communications between several connected tone remotes
without transmitting over the radio. When the INTER key is pressed and held, the audio is routed on the line
without the Guard Tone activating the transmitter. Other tone remotes on the same line will hear the audio
automatically. No cross mute is available in intercom mode since there is no Guard Tone present.
MONITOR: Pressing the MONITOR key will allow the user to monitor the channel before pressing the SEND key
to make a call. If a conversation is heard then another co-channel user presently “owns” the channel and should
not be interrupted.
1 ABC 2 DEF 3
GHI
4 JKL 5 MNO 6
PQRS
7 TUV 8 WXYZ 9
MENU
* OPER 0 CLR #
FREQ INTER
MONITOR
SEND
◄SCROLL ►
PWR - LINE/SUP SEND - F1/F2
12:00
Freq: 01 Func: 05

10
SEND: Pressing SEND will transmit the high-level guard tone for 120 msec, followed by the frequency tone for 40
msec, followed by the low-level guard tone that keys the radio with the voice and dialing riding over the low-level
continuous tone.
0-9 Keys: Used in conjunction with the FREQ key these number keys can be used to select the
frequency/function tone. The number keys can also be used to dial DTMF.
*/MENU: Not used on the TRC-1.
#/CLR: When CLR is pressed, any keyboard entries in the buffer will be cleared.

11
OPERATION
Frequency versus Function: The F1-F17 tones are referred to, industry wide, as Function Tones, but are used
as frequency selector tones to control the base station radio channel selection. Midian, with it’s TTC-1 tone
remote adaptor can use the Function Tones for either frequency selection or for controlling a function for remote
monitoring and control. These functions can be used for turning on/off a scrambler in the TTC-1, controlling voice
prompts from the TTC-1, or providing outputs from the TTC-1 to the TTC Option A (wild card module) for remotely
controlling equipment. If using the TRC with the LCD Option (TRC Option I) the TRC will display the Frequency
and the Function. For example, Frequency 1 can be selected while controlling Function 5 and the display will
show “Freq: 01 Func: 05”. A frequency and function should not share the same Function Tone. For example, if
only channel 1 and 2 at the base station need to be controlled (F1-F2), this leaves F3-F17 for use as function
control. If 16 channels need to be controlled at the base station (F1-F16), this leaves F17 for use as function
control.
Frequency Selection: To change the channel of the radio (F1 up to F16), press the FREQ button followed by a
single digit number for F1-F9 or a double digit number for F01-F16. When the Function Tone is selected, the TRC
sends the High-Level Guard Tone followed by the selected Function Tone to the tone remote adaptor to change
the channel of the radio. If using with other Midian TRC’s (revision G and higher), the paralleled remotes will also
show the channel change on the display.
Function Selection: To control a function press the FREQ button followed by a single digit number for F1-F9 or a
double digit number for F10-F16. When the Function Tone is selected, the TRC sends the High-Level Guard Tone
followed by the selected Function Tone to the TTC-1 to command the function control. Note: The selection of a
function does not cancel any frequency selection. If the TRC is on Frequency 1 and Function 5 is selected, the
tone remote adaptor will remain on Frequency 1.
Transmitting: After selecting the desired Function Tone for frequency selection, pressing and holding the SEND
key will generate the High-Level Guard Tone followed by the continuous Low-Level Guard Tone. The user speaks
into the microphone of the TRC and the voice goes out over the Low-Level Guard Tone.
DTMF Dialing: After selecting the desired Function Tone for frequency selection, type the desired DTMF
sequence on the number keys (0-9) followed by the SEND key. The TRC will generate the High-Level Guard
Tone followed by the continuous Low-Level Guard Tone. The DTMF tones will go out over the Low-Level Guard
Tone. The user can then follow the tones with voice if desired.
Monitor: Prior to transmitting or dialing, the user should Monitor the channel to see if there is activity on the
channel. If there is activity, the user should wait until the channel is clear. Pressing the MONITOR button sends
the High-Level Guard Tone followed by the Monitor Function Tone to the tone remote adaptor giving it a
command to open the squelch of the radio. Depending on the tone remote adaptor this can be momentary or
latched. If momentary, the tone remote adaptor will close the squelch of the radio after a set amount of time. If
latched, the squelch will remain open until the tone remote adaptor receives a second Monitor command from the
TRC.
Receiving: When a field radio keys up, the tone remote adaptor passes the voice down the line to the TRC. The
voice will then be passed through to the internal speaker of the TRC.
Line 2/Supervisor Capability (* + #): If the TRC is ordered with TRC Option E, then the TRC is equipped with
the Line 2/Supervisor Capability. Line 2 is used for toggling between 2 different base station radios and
Supervisor is used to shut down any paralleled remotes. Pressing the * and # keys simultaneously activates the
Supervisor or the Line 2 mode depending on the options installed in the unit. Pressing the keys again deactivates
the Supervisor or the Line 2 mode. When activated LED 1 changes from red to orange.
Memory Dialing: The TRC supports up to 9 memory dials (1-9). Press and release the * key, followed by the
desired 1-9 number key for 1 second.
Last Number Redial: The TRC can recall the last sequence dialed by pressing and releasing the * key followed
by the SEND key.

12
PRODUCT PROGRAMMING
Memory Dial: To set up the memory dial locations first enter configuration mode by entering “*FREQ 0” on the
keypad. To exit programming mode enter “* 0 0”.
Each memory dial location can support up to 16 DTMF digits (0-9, *, #). To enter 0-9 press the associated number
key. To enter a *, press the * key three times. To enter a #, press *#*. For example to have “#1234” as a memory
dial you would enter “*#*1234” into the register. Enter the desired DTMF sequence followed by * and the memory
dial location number which would be 60-69 as below. If a mistake is made during entry, pressing the # key clears
the register.
dddddddddddddddd*61 – Memory Dial Slot #1
dddddddddddddddd*62 – Memory Dial Slot #2
dddddddddddddddd*63 – Memory Dial Slot #3
dddddddddddddddd*64 – Memory Dial Slot #4
dddddddddddddddd*65 – Memory Dial Slot #5
dddddddddddddddd*66 – Memory Dial Slot #6
dddddddddddddddd*67 – Memory Dial Slot #7
dddddddddddddddd*68 – Memory Dial Slot #8
dddddddddddddddd*69 – Memory Dial Slot #9
dddddddddddddddd*60 – Memory Dial Slot #0
Once memory dial programming is completed, exit configuration mode by entering “*00” on the keypad.
Function Tone Frequency Programming: The Function Tone Frequencies are programmable.
However, most applications do not require this to be done. Therefore, to avoid confusion for the
majority of users, for those requiring this please contact Midian for assistance.
Programmable Parameters: The following features are programmable in the TRC. To enter
programming mode enter “* FREQ 0”. To exit programming mode enter “* 0 0”.
Dialing Tones Hang Time Delay: This field is programmed with T*42, where T equals the time in seconds
(i.e. 2 equals 2 seconds). This field is defaulted to 2 seconds. This keeps the Low-Level Guard Tone keying
the transmitter after tones are dialed, so that the decoded pager does not drop out due to carrier loss.
External Handset Option: If ordered with the TRC Option C this field will be preprogrammed. This field is
programmed with A*43, where A equals either 0 for disabled or 1 for enabled.
F10-F17: If you wish to use F10-F17 function tones you should enable this feature. This field is programmed
with A*54, where A equals either 0 for disabled or 1 for enabled.
Line-2/Supervisor Option: If ordered with the TRC Option E this field will be preprogrammed. This field is
programmed with A*44, where A equals either 0 for disabled or 1 for enabled.
4-Wire Option: If ordered with the TRC Option F this field will be preprogrammed. This field is programmed
with A*57, where A equals either 0 for disabled or 1 for enabled.
Key-Up Delay: This field is programmed with TT*45, where TT equals the time in hundreds of milliseconds
(i.e. 05 equals 500 milliseconds or 12 equals 1200 milliseconds). This field is defaulted to 04 for 400
milliseconds.
Crossmute: This field is programmed with A*49, where A equals either 0 for disabled or 1 for enabled. This
field is defaulted to 0. Enabling the Crossmute feature keeps feedback from occurring with multiple tone
remote controllers in the same room or from having to listen to other tone remotes’ conversations in the same
building.
Off-Hook Polarity: If ordered with the TRC Option C this field will be preprogrammed. This field is
programmed with A*50, where A equals either 0 for Active Low or 1 for Active High.

13
External PTT Polarity: If ordered with the TRC Option C this field will be preprogrammed. This field is
programmed with A*51, where A equals either 0 for Active Low or 1 for Active High.
Side Tone Jumper: This field is programmed with A*52, where A equals either 0 for Not Installed or 1 for
Installed. This feature is only available when the TRC Option C (Handset) is ordered and JP302 is installed.
The TRC will allow side tone audio to be passed back to the earpiece on the externally attached handset.
Automatic External Monitor Option: This field is programmed with A*53, where A equals either 0 for
disabled or 1 for enabled. This field is defaulted to 1. This feature is only available when the TRC Option C
(Handset) is ordered. When enabled the TRC will automatically transmit the Monitor function sequence to the
tone remote adaptor when the operator picks up the handset.
Reset Factory Defaults: To reset the unit back to factory defaults enter *80. This will erase all custom
programming you have entered.

14
TRC OPTION H: MULTI-FORMAT DIALING
The TRC Option H gives the TRC the ability to dial in DTMF, 2-Tone, 5-Tone or Pulse Tone. There are three
parameters that will need to be programmed into the TRC; Dialing Format, Dialing Time 1 and Dialing Time 2.
Enter programming mode by entering “* FREQ 0” on the keypad.
Dialing Format: To program the desired dialing format enter the two digit format number from the table below
followed by *46 (i.e. 04*46 for Motorola General). Note: QC2 stands for Motorola Quick Call 2.
# Format # Format # Format # Format
01 AvCall 10 Motorola F – QC2 20 Motorola R – QC2 34 DDZVEI – 5-Tone
01 QuickCall 1 11 Motorola G – QC2 21 Motorola S – QC2 35 CCIR1 – 5-Tone
02 GE Type 99 12 Motorola H – QC2 22 Motorola T – QC2 36 EEA – 5-Tone
03 Reach Slow 13 Motorola J – QC2 23 Motorola U – QC2 37 NATEL – 5-Tone
04 Motorola General QC2 14 Motorola K – QC2 24 Motorola V – QC2 38 MODAT – 5-Tone
05 Motorola A – QC2 15 Motorola L – QC2 25 Motorola W – QC2 50 2805 Hz Pulse Tone
06 Motorola B – QC2 16 Motorola M – QC2 30 EIA – 5-Tone 51 1500 Hz Pulse Tone
07 Motorola C – QC2 17 Motorola N – QC2 31 Eurosignal – 5-Tone 59 Plectron
08 Motorola D – QC2 18 Motorola P – QC2 32 ZVEI – 5-Tone 60 DTMF
09 Motorola E – QC2 19 Motorola Q – QC2 33 DZVEI – 5-Tone
Dialing Time 1: This field is programmed with TTTT*47, where TTTT equals the time in milliseconds (i.e. 0060
equals 60 msec or 1000 equals 1 second). For DTMF this sets the tone on time. For 2-Tone this sets the A tone
time. For 5-Tone this sets the time of the first tone. For Pulse Tone this sets the time of the tone break.
Dialing Time 2: This field is programmed with TTTT*48, where TTTT equals the time in milliseconds (i.e. 0060
equals 60 msec or 1000 equals 1 second). For DTMF this sets the tone off time. For 2-Tone this sets the B tone
time. For 5-Tone this sets the time of each subsequent tone. For Pulse Tone this sets the time of the tone make.
To exit programming mode enter “* 0 0” on the keypad.
Entering a user ID number, often called a CAP code, is straightforward for most of the encoding formats. For
example, when encoding DTMF or 5-tone, the digits 0-9 are simply typed in directly. For Motorola Quick Call 2,
GE Type 99 and Reach you simply enter the 3 digit cap code. Some formats do not allow for this straightforward
approach. These are Plectron, Quick Call I, and Avcall. This section explains how to enter a code in these
formats.
Plectron Encoding: To encode Plectron, four digits must be used. The first two digits represent the 1st tone, and
the 2nd two digits represent the 2nd tone. Simply locate the code associated with each tone from the table. For
example, the tone sequence 454.6 + 2688 would be entered as 1253.
Plectron Tones
01 282.2 08 382.2 15 517.7 22 701 29 950 36 1287 43 1743 50 2361 57 3197
02 294.7 09 399.2 16 540.7 23 732 30 992 37 1344 44 1820 51 2465 58 3339
03 307.8 10 416.9 17 564.6 24 765 31 1036 38 1403 45 1901 52 2574 59 3487
04 321.4 11 435.3 18 589.7 25 799 32 1082 39 1465 46 1985 53 2688
05 335.6 12 454.6 19 615.8 26 834 33 1130 40 1530 47 2073 54 2808
06 350.5 13 474.8 20 643 27 871 34 1180 41 1598 48 2165 55 2932
07 366.0 14 495.8 21 672 28 910 35 1232 42 1669 49 2260 56 3062

15
Avcall & Motorola Quick Call 1: Avcall & Quick Call 1 are dual-tone formats, which means a pair of tones are
sent simultaneously. Two tone-pairs are sent, meaning that 4 tones in total must be selected. Like Plectron 2
digits are entered for each tone. Locate the desired tone in the table to find its corresponding code. A total of 8
digits must be entered. For example, the tone sequence 645.7 & 312.6 + 881.0 & 1479.1 would be entered as
07001015.
Avcall & Motorola Quick Call 1 Tones
00 312.6 07 645.7 14 1333.5 21 668.3 28 412.1 35 851.1 42 473.2 49 346.7
01 346.7 08 716.1 15 1479.1 22 741.3 29 457.1 36 944.1 43 524.8 50 977.2
02 384.6 09 794.3 16 398.1 23 822.2 30 507.0 37 371.5 44 582.1 51 1084.0
03 426.6 10 881.0 17 441.6 24 912.0 31 562.3 38 1047.1 45 645.7
04 473.2 11 977.2 18 489.8 25 358.9 32 623.7 39 1161.4 46 716.7
05 524.8 12 1083.9 19 543.3 26 1011.6 33 691.8 40 384.6 47 794.3
06 582.1 13 1202.3 20 602.6 27 1122.1 34 767.4 41 426.6 48 881.0

16
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 signaling tones 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 TRC. This can be done at the factory upon request
(recommended). It also requires that the guard tone and notch filters on the tone remote adapter 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. Many tone remote adapters 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 2274, 2196, and 2121 Hz to represent the digits
6, 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, MODAT, NATEL, QUICK CALL I,
and QUICK CALL II.

17
THEORY OF OPERATION
Analog Circuit
RX Audio Input Path: RX audio from a tone remote adaptor at the remote site travels down the phone line to the
RJ-11 line interface connector PL-1. Line 1 uses the standard red/green Telco ring tip on positions 5 and 6 of the
RJ-11 cable or pins 5 and 6 of the RJ-45 10-pin connector. This signal is fed into a transient absorber across the
line, then through an auto-resettable polyswitch fuse to another set of transorbs that can shunt a signal to ground
if the ground lead is tied to Earth. There are then 2 capacitors across the line, which also go to Earth to remove
RF. The audio signal is then fed into transformer T201 through jumpers JP202 and JP203 or Line 2 relay K201.
From the bottom winding of T201 audio is fed to jumper JP204 contacts 1 and 2 or contacts 2 and 3 if using T202
in a 4-wire duplex configuration. From JP204 audio is fed into the RX Input Gain Pot RP-306 where the output
level of the RX line amp U302 is typically set to 200 mV p-p with –20 dbm from a Line Test Set tone generator.
There is a disable transistor Q303 that can mute the incoming audio under microprocessor control. Coming out of
the RX line amp the audio is passed to the compression circuit U102B. The audio output of the compressor is
also about 165 mV p-p and will change no more than 3 db over a 30-35 db input change. The audio then goes
into the RX Bandpass amplifier U301D and the output of this Bandpass is fed into the Guard Tone detector which
turns on the busy light and depending on how the unit is programmed can activate the crossmute function when
another unit in the same room is transmitting to prevent howling and feedback. The output of the Bandpass is also
fed over to the RX notch filter U301C through a nulling pot. When the Bandpass filter has been tuned to the
appropriate frequency for the desired Guard Tone (usually 2175 Hz) its output is fed through the nulling pot and
R303 and R346 where it mixes with audio from R324 coming from the compressor. These two signals cancel at
the summing input of Notch filter U301C thus removing the continuous Guard Tone audio leaving only the
resulting voice and dialing audio to be transmitted through the volume control SR601B to the speaker amplifier.
Keypad beeps are also input on this same pot to be heard out the speaker. When the handset is taken off-hook,
the magnetic reed switch located inside of the handset opens it’s contact which signals the microprocessor to
activate transistor Q302. Activating transistor Q302 mutes the speaker amplifier. Audio from U301C is fed into
ear level RP304 which drives the earpiece driver Q303B to drive the handset earpiece. There is also an ear mute
transistor Q304 that allows the microprocessor to mute the earphone. There is also a jumper JP302 that feeds
handset mic audio back into the earpiece for sidetone. This jumper should not be used in 4-line duplex mode.
There is another jumper JP201 that feeds DTMF and paging and dialing tones into the RX audio path so that they
can be heard during the dialing time.
TX Audio Output Path: Mic bias is developed with R100, R134 and R101. This provides mic bias to either the
internal mic, or gooseneck mic. These are all electret type mics. When using the internal mic or gooseneck mic,
Q306 switches audio into the mic amp U101A where the gain is set by RP101. Q101 on the input of the mic amp
kills mic audio during the High-Level function tones and dialing times. Coming out of the mic amp the audio level
is approximately 200 mv peak to peak where it is fed into the compressor U102A. The audio out of it is also about
200 mv peak to peak and will change no more than 3 db over a 30-35 db input change. It is then fed into notch
filter U103C and U103D. This notch filter is usually set to the standard Guard Tone of 2175 Hz and is designed to
remove 2175 Hz components from the voice so that they do not mix with the 2175 tone generator and cause
phase cancellation and thus momentary breaks in the Low-Level Guard Tone. The notch filter feeds into the audio
mixer along with the signaling and dialing tones from the digital to analog converter. The tones and voice out of
the audio mixer are presented to the TX line level pot RP202 and then to the line amplifier U201A. U201A then
feeds the top winding of T201. When the line level pot RP202 is set all the way to maximum it is sufficient to drive
a single phone line with up to 8 additional tone remotes to about +10 db on the high level guard tone.
The regulator has an input from a wall charger of around 16-20 volts which is passed through a auto-resettable
polyswitch F601 into transient absorber TZ601, then through the volume control on/off switch SR601A to an RF
bypass cap C602, across several filter caps into the input of the 13.4 volt regulator. D601 is a reverse polarity
diode that will blow the auto-resettable polyswitch if the power is reversed. Powering off for one to two seconds
will reset the polyswitch. The output of the 13.4 volt regulator is fed to all of the analog circuitry on the analog
schematic page. U303A has a voltage divider R373 and R374 that creates the analog pseudo ground reference to
all of the op amps on the analog schematic page.

18
Digital Circuit
There are three microprocessors on the digital schematic page. U402 controls the keypad interface and also talks
to the LCD if installed. In addition it generates the keyboard beeps to the speaker amp, it controls the speaker
mute when the handset is taken off-hook. Additionally, it controls the Line 2/Supervisor to the line relay on the
analog page.
Microprocessor U401 generates the Guard Tone, function tones and signaling tones on its B0-B7 port. These
tones are fed into U405 the DAC output over to the analog page. U401 also controls PTT disable, PTT mic enable
and ear mute. Both of these microprocessors get their voltage from 5-volt regulator U601.
Microprocessor U403 controls the printer option U404 and decodes the high and low level guard tone, as well as
the function tones.
Microprocessor U407 is the real time clock chip with battery back-up if installed.

19
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

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