Vega 1223C User Manual

Technical Manual

1223C/1224 Series Tone-Remote Adapters

1223C Series Tone-Remote Adapter 1224 Expansion Module

098-0348
Rev. C

Contents

General ........................................................1

Options ........................................................1

Operation ......................................................2

Installation .....................................................3

1224 Installation .................................................5

Tuning.........................................................5

1223C to1224 Tuning Instructions...................................5

Level Adjustments ...............................................5

Theory of Operation ..............................................6

Warranty (Limited)...............................................8

1223C Parts List .................................................9

Specifications ..................................................15

General

The Vega 1223C tone-remote adapter provides
a reliable means of remotely controlling a
two-way radio base station. It utilizes
industry-standard control tone frequencies and
timing to provide normal remote system
functions of transmitter keying and CTCSS
tone squelch monitoring.

Adding the optional Model 1224 expansion
module extends the capability to selecting one
of up to four frequencies or up to two paired
functions per module, for control of properly
equipped base stations. Both the 1223C and
1224 are designed to plug into telco shelves
(such as Tellabs Type 10 and Wescom or
Dantel 400 Type).

The adapter is mounted in or near the base
station it is to control, and is connected via hard
wire to applicable connection points. Interface
to the remote control console is through any
voice-grade medium, such as 600-ohm twisted
pair, leased telephone line, or microwave link.

Options

Model 1224 Expansion Module

This four-frequency decoder extends the
capability of the basic unit to accommodate up
to a four-frequency transmitter, or it can
provide two “on/off” ancillary base-station
functions of properly equipped base stations. A
second 1224 can be added to double the number
of frequencies or paired functions.

LPO-23 Lightning and Transient Protector

These gas-discharge tubes provide lightning
and transient protection to maintain system
integrity in a difficult environment. Vega
highly recommends the incorporation of this
option for each installation.

TO-23 Transformer Isolation

Isolation for transmit and receive interfaces is
provided by a TO-23 Transformer isolation
option. Transmitter line input isolation is
provided by a 600-ohm CT:600-ohm CT
transformer. Receiver output isolation is
provided by a 10-kilohm CT:10-kilohm CT
transformer.

1

Compatibility
Vega Tone Remote Consoles

The following Vega consoles are fully
compatible with 1223Cs:

Model Number Description

C-510C/C-511/C-512 Two-frequency transmit
C-514B Four-frequency transmit
C-516 Six-line/two frequency
C-1614 Six-line/four frequency
C-582/C-583 Eight-frequency transmit

C-5110/C-5111/C-5112/C-5200 Ten-line/four frequency

Monitor. A “monitor” function disables the
base-station receiver CTCSS (Continuous Tone
Coded Squelch Signaling) sub-audible-tone-decoder
circuit, as required by FCC regulations, on stations so
equipped. The monitor function is accomplished by
decoding a 2050 Hz tone command, and providing a
jumper-selected switched transistor or relay-closure
output, to turn off the radio receiver CTCSS
decoder, allowing the console operator to
monitor the channel for other users before
keying the transmitter. A monitor LED is
provided on the front panel.

Other Vega consoles may be compatible with
1223Cs. Consult the factory for compatibility
information.

Other Manufacturers Tone-Remote
Consoles

Other consoles (such as Motorola, Ericsson and
GE) using industry-standard control tone
frequencies and timing are generally
compatible with these modules. If in doubt,
consult the factory for compatibility.

Operation

The 1223C decodes industry-standard tone
control sequences to provide the following
functions: PTT (push-to-talk/transmitter key);
CTCSS tone squelch receiver monitoring, and
with the optional 1224 expansion module,
selection of one of up to four frequencies for
transmission, or selection of up to two paired
functions, on base stations so equipped. A
second 1224 can be added to double the number
of frequencies or paired functions.

The unit is capable of two-wire or four-wire
operation, and is easily converted by means of
jumper plugs. In addition, full-duplex operation
can also be accommodated in the four-wire
mode, by a simple jumper plug.

PTT. Base-station keying is accomplished by
decoding the tone-control command, and
providing a jumper-selected switched transistor
or relay-closure output. Transmitter keying is
indicated by a front panel LED. During PTT
operation, the control tone portion (2175 Hz,
hold tone) of the voice-plus-tone signal
received from the remote console is removed
from the transmit audio applied to the base
station.

Three modes of monitor operation are
provided, any one of which is easily jumper
selectable.

1. Timed Mode. In this method of operation,
the monitor function operates for a timed period
(adjustable for up to 9 seconds) or until a PTT
command is decoded.

2. Latched Mode. Upon receipt of the monitor
command, the function is latched on, until reset
by a PTT command.

3. Timed/Refresh mode. A timed monitor
function is initiated by receipt of any tone
command. Any command received during the
timed period refreshes the timer for another full
cycle. This mode is extremely useful for
systems in which frequent dispatch/mobile
interchanges occur, or where frequent
frequency selections are made.

Alternate Function Capability. On single-user
stations not equipped for CTCSS operation, the
monitor function may be used for another
purpose, such as interrogation of a
status-reporting system at the station site.

Frequency Selection. Frequency selection is
provided by the optional Model 1224
expansion module(s). Each module can select
one of up to four frequencies. The number of
selectable frequencies varies with the number
of modules chosen. As shipped, one of the
frequency-select relays is always latched on,
and upon decoding a frequency-select
command, the latched relay is reset and the
relay associated with the command is latched
on (1-of N mode). Relay outputs can be
jumpered for latched or momentary outputs.

2

Ancillary Functions. The 1224 expansion
module(s) can also be jumper selected to
provide up to two paired “on/off” toggle
functions per module, for control of properly
equipped base stations. Relay outputs can be
jumpered for latched or momentary outputs.

Installation

Connect an external 10- to 16-volt
semiregulated DC power supply to the card
shelf, with ground to J2-39 and positive to
J2-47.

Connect the two-wire leased line to J2-4 and
J2-6. For four-wire operation, move JP6 to B,
connect the outgoing line to J2-4 and J2-6, and
connect the incoming line to J2-8 and J2-10.
Also move JP4 to B if full-duplex operation is
desired.

Connect J2-38 to the transmitter mic audio
input, and J2-36 to the transmitter mic audio
return. If the TO-23 radio-interface isolation
transformer option is not installed, set JP12 and
JP13 both to the “A” position. If the TO-23
option is installed, set JP12 and JP13 both to the
“B” position.

If the mic input is a high-impedance type,
shielded cable is recommended. If the radio has
a high-level mic input, move JP7 to the “B”
position.

Connect the radio receiver audio output to J2-14
and J2-16. This must be an audio source after the
squelch circuit, to prevent sending continuous
noise to the remote console(s). If the radio
receiver audio output is single-ended and the
TO-23 option is not installed, be sure that the
“low” or “grounded” side of the radio receiver
audio output is connected to J2-16. If the TO-23
option is not installed, set jumpers JP10 and JP11
both to the “A” position; if the TO-23 option is
installed, set jumpers JP10 and JP11 both to the
“B” position.

3

If a high-impedance point in the receiver is
used, shielded cable is recommended. If the
speaker output is used, move JP5 to B. Note that
when the speaker output is used, the radio
volume control will affect the audio output
level at J2-14.

Connect the radio PTT circuit to the PTT relay
contact terminals of the panel. Connect the
radio “monitor” circuit to the MON relay
contact terminals. Refer to the schematic.

1223C/1224 Block Diagram

4

1224 Installation

Make the following essential connections
between the 1223C and 1224 boards: J2-53 to
J3-53, J2-50 to J3-50, J2-48 to J3-48, J2-46 to
J3-46, J2-45 to J3-45, J2-40 to J3-40, and J2-43
to J3-44 (not J3-43).

When one or more 1224 models are installed,
connect radio-frequency control circuits to the
function-control relay output terminals on the
PC board(s). Usually the common of each relay
contact switch is grounded and the normally
open contact connects to the radio
frequency-control terminals. Refer to the
schematic.

A few radios (such as some GE models) have
separate transmitter and receiver frequency
controls. Use the above connections for
transmitter frequency controls and connect the
receiver frequency controls to the second set of
relay contacts available at solder-pad terminals.
Refer to the schematic.

The 1223C line transformers are not designed
to operate on lines carrying direct current. If a
DC voltage is on the line, isolate with external
capacitors. If the line termination must conduct
direct current, install a 600:600-ohm
transformer designed for the current involved.

Tuning

All models have been factory-tuned to the
following frequencies:

Guard Tone/PTT Tone: 2175 Hz

MON Function Tone: 2050 Hz

Frequency-Select Function Tones

(where used)

F1: 1950 Hz F2: 1850 Hz F3: 1750 Hz F4: 1650 Hz

1223C to 1224 Tuning Instructions

1. Connect audio source to R52 lead on 1223c

through a 1uf dc blocking cap.

Relay/LED defeats and active-low
open-collector logic outputs have been
provided for special installations. Refer to the
schematics.

Transient protection has been provided near all
audio inputs and outputs. This is adequate for
transients up to at least 100 volts, but external
transient protection such as gas-discharge or
MOV devices should be installed to provide
some protection from very high-voltage
transients such as from lightning.

Although there is no complete protection from
lightning, gas-discharge devices such as North
Supply #S-561034 (two-wire) or S-561034
plus S-561035 (four-wire) provide a high
degree of protection when a nearby earth
ground is connected.

For additional protection , provisions have been
made on the 1223C for installation of either
Model LPO-23 gas-discharge-tube protectors.
An earth-ground terminal is also provided.

Vega will not replace units under warranty that
have obvious high-voltage damage such as
vaporized PC-board traces or melted
components.

2. Insert required decode signal at 0dbm for F1
of 1224 to be retuned.

3. Connect O’scope or rms. volt meter to TP3
and tune R39 for Max signal.

4. Repeat the same for F2 using TP4 and R53.

5. Repeat the same for F3 using TP1 and R6.

6. Repeat the same for F4 using TP2 and R1.

Level Adjustments

Level adjustments normally are required only
at the time of installation or due to base-station
changes.

Important: All test points have DC bias on
them. Use the “output” AC terminals and
scales on your meter, which places a DC
blocking capacitor in series with the meter.

1. Line Drive Adjustment

the receiver so that continuous noise is present.
Connect the meter to J2-4 and J2-6 (line should
also be connected) and adjust R94 (line output
level) for the desired line level (usually 0 dBm
or 0.8 V

rms

).

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