Ritron SST-444 User manual

TYPE OF EXHIBIT: INSTRUCTION MANUALS
FCC PART: 2.1033 (c)(3)
MANUFACTURER: RITRON, INC.
505 West Carmel Drive
Carmel, IN 46032
MODEL: SST-444
TYPE OF UNIT: UHF-FM Handheld Transceiver
FCC ID: AIERIT13-450
DATE: July 7, 2000
Included in this exhibit is a draft of the Maintenance and Operating Manual for RITRON Model Patriot
SST-444 UHF-FM Handheld Transceiver.
Specifically, this manual includes a technical description of the SST-444 sufficient to establish compliance
with the technical standards of the applicable rule part(s).
This includes, but is not limited to, the following items required under FCC Part 2.1033 (c):
(2) FCC Identifier.
(3) A copy of the installation and operating instructions.
(4) Type of emission.
(5) Frequency range.
(6) Range of operating power, and means to provide variation in operating power.
(7) Maximum power rating.
(8) DC voltage chart.
(9) Tune-up procedure.
(10) A description of all frequency determining and stabilization circuits. A description of the circuits
used to suppress spurious radiation, limiting modulation, and limiting power.
(12) Drawing with labels for controls and complete circuit diagrams.
Signed: Michael A. Pickard - Project Engineer

2
TABLE OF CONTENTS
SECTION TOPIC PAGE
1. SST-444 SPECIFICATIONS
GENERAL 4
RECEIVER 5
TRANSMITTER 6
2. INTRODUCTION
GENERAL 7
Inspection 7
Model Identification 7
FCC REGULATIONS
Licensing 7
Safety Standards 7
3. BATTERY CARE
CHARGING 8
BATTERY REPLACEMENT 9
PRECAUTIONS 9
4. DESCRIPTION OF CONTROLS AND CONNECTORS 10
Fig. 2 Controls and Connectors 11
Belt Clip Installation 11
5. OPERATION
On-Off/Volume 12
Receive 12
Monitor 12
Selective Signaling Squelch 12
Battery Saver 12
Transmit 13
Channel Selection 13
WHAT THE RADIO TONES MEAN
Power On/Self Check “OK 13
Error Tones 13
Channel Select 13
Tone Squelch 13
Recharge Battery Alert 13
OPTIONAL RADIO TONES
Receiver Squelch Tone 14
Busy Channel Inhibit 14
Transmitter Time Out 14
TROUBLESHOOTING
General 15
Battery 15
Error Tones 15
Tone Coded Squelch 16
6. PROGRAMMING THE RADIO
PTT (PUSH-TO-TALK) PROGRAMMING
Placing the Radio in PTT Programming Mode 17
How To Find Out What Is Already Programmed 17
PTT Programming the Radio 18
PTT Programming Mistakes 18
Return To Normal Operation 18
Table 1 – PTT Programming Frequency Table 19

3
Table 2 – Quiet Call Codes and Frequencies 19
COMPUTER SOFTWARE COPYRIGHTS 19
PROGRAMMING THE RADIO USING A PC COMPUTER 20
Programmable Features 20
Description of Features 21
7. SST-444 THEORY OF OPERATION
INTRODUCTION 22
POWER SUPPLY AND VOLTAGE DISTRIBUTION 22
Power Strobe 22
Low Battery Voltage Detection 22
REFERENCE OSCILLATOR 23
SYNTHESIZER 23
Pin Numbers 23
Prescaler Divider / Synthesizer Controller 23
VCO / Buffer Amplifiers 24
Oscillator Modulation 24
DIGITAL POTENTIOMETERS 24
RECEIVER 25
RF Amplifier 25
1st Mixer 25
FM Receiver Subsystem 25
Voice / Tone Conditioning in Receiver Mode 25
Voice Band 26
Sub-Audible 26
Audio Amplifier 26
ANTENNA SWITCHING / LOW-PASS FILTER 26
TRANSMITTER 27
Keying 27
+VTX Supply 27
Power Amplifier 27
Voice/Tone Conditioning in Transmit Mode 27
Voice Band 27
Sub-Audible 28
MICROCONTROLLER 28
8. SST-444 ALIGNMENT PROCEDURE
RECOMMENDED TEST EQUIPMENT 30
RADIO PREPARATION 30
REFERENCE FREQUENCY 31
MODULATION BALANCE 31
TRANSMITTER TONE DEVIATION 31
TRANSMITTER VOICE DEVIATION 32
TRANSMITTER POWER 32
RECEIVER SENSITIVITY AND SQUELCH 32
RECEIVER NOISE SQUELCH 33
SYNTHESIZER 33
9. SST-444 VOLTAGE CHART
Measurement Conditions 34
SST-444 Voltages 34
10. SST-444 SCHEMATIC REFERENCE PARTS LIST 40
11. SST-444 CASE ASSEMBLY PARTS LIST 47
12. SCHEMATIC AND PART PLACEMENT DRAWINGS 48

4
IMPORTANT MAINTENANCE/REPAIR INFORMATION
Surface Mount Repair
RITRON surface mount products require special equipment and servicing techniques. Improper servicing
techniques can cause permanent damage to the printed circuit boards and/or components, which is not
covered by RITRON’s warranty. If you are not completely familiar with surface mounted component repair
techniques, RITRON recommends that you defer maintenance to qualified service personnel.
Precautions for Handling CMOS Devices
This radio contains complementary metal-oxide semiconductor (CMOS) devices, which require special
handling techniques. CMOS circuits are susceptible to damage by electrostatic or high voltage charges.
Damage can be latent, with no failure appearing until weeks or months later. For this reason, take special
precautions any time you disassemble the radio. Follow the precautions below, which are even more
critical in low humidity environments.
1) Storage/transport - CMOS devices that will be stored or transported must be placed in conductive
material so that all exposed leads are shorted together. CMOS devices must not be inserted into
conventional plastic “snow” or plastic trays of the type that are used for other semiconductors.
2) Grounding - All CMOS devices must be placed on a grounded bench surface. The technician that will
work on the radio/CMOS circuit must be grounded before handling the radio. Normally, the technician
wears a conductive wrist strap in series with a 100K Ohm resistor to ground.
3) Clothing - Do not wear nylon clothing while handling CMOS circuits.
4) Power off - Remove power before connecting, removing or soldering a PC board that contains CMOS
devices.
5) Power/voltage transients - Do not insert or remove CMOS devices with power applied. Check all
power supplies to be used for testing CMOS devices, making sure that no voltage transients are
present.
6) Soldering - Use a grounded soldering iron for soldering CMOS circuitry.
7) Lead-straightening tools - When straightening CMOS leads, provide ground straps for the tool used.
PC Board Removal - Special Tool
RITRON recommends using a knurled nut tool to remove the slotted knurled nuts that secure the charge
and audio jacks on top of the radio. You will need two sizes of this tool, one for each jack size. Mouser
Corporation is one source, stock number 382-0004 (2.5mm jack) and 382-0006 (3.5mm jack). You can
reach Mouser sales and distribution center at 1-800-346-6873.
Properly Attach the Synthesizer Shield
The synthesizer shield should not be removed, unless a component must be replaced. This shield is
soldered to the main PC board.
Re-assembly - Speaker Magnet, Battery Voltage on Connector Pin
The speaker magnet will pick up clipped leads and other small metal objects from your bench top. Even
tiny objects on the diaphragm will cause the speaker to buzz. Make sure the speaker is free of foreign
objects before reassembling the radio.
Radio Transmitter Power Measurements
The SST-444 was designed to produce a minimum of 3.5 Watts of Transmitter power at nominal battery
voltage (+7.2 VDC), throughout the radio’s operating frequency range. Measurements are made with the
RITRON SST-SRVBD RF service module connected to the radio antenna terminal. The transmitter was
designed with close tolerances to prevent RF power output from exceeding specifications and reducing
battery life.

5
SST-444 SPECIFICATIONS
GENERAL
FCC ID: AIERIT13-450
FCC Rule Parts: 22, 74, 80, 90
Frequency Range: 460 to 470 MHz standard
Max. Freq. Separation: 10 MHz
RF Channels: Conventional: 4 Channels, Independent TX/RX frequencies.
Synthesizer Step Size: 12.5 KHz
Frequency Stability: +/-2.5 PPM (-30 to +60 C) TX/RX
Tone/Code Signaling: CTCSS (Quiet Call)
Digital Coded Squelch (Digital Quiet Call)
Power Supply: +7.5 VDC, 800 mAH rechargeable NiCd battery pack standard
+7.5 VDC, 1500 mAH rechargeable MiMH battery pack optional
Battery Drain:
Standby: 52 mA
Sleep: 12 mA
Avg. Standby with Power Saver: 24 mA
Receive: 125 mA
Transmit: 1500 mA @ 4 Watts
500 mA @ 1 Watt
Battery Life:Standard battery (800 mAH) @ 90/5/5 Duty Cycle
8.2 Hrs, Battery Saver On, TX High Power
16.8 Hrs, Battery Saver On, TX Low Power
6.2 Hrs, Battery Saver Off, TX High Power
10.2 Hrs, Battery Saver Off, TX Low Power
High capacity battery (1500 mAH) @ 90/5/5 Duty Cycle
13.3 Hrs, Battery Saver On, TX High Power
27.3 Hrs, Battery Saver On, TX Low Power
10.2 Hrs, Battery Saver Off, TX High Power
16.7 Hrs, Battery Saver Off, TX Low Power
Dimensions: 4.75”H x 2.2”W x 1.43”D
Weight: 11.5 oz. with battery pack
Enclosure Material: Lexan Polycarbonate
Environmental: Splash resistant and shock and vibration per RITRON Drop Test
(6 ft. drop onto concrete on all six sides)
Antenna Fitting: 1/4" - 32 x 1/4" threaded
External RF Test Jack: Antenna connector with RITRON SST-SRVBD test device

6
SST-444 SPECIFICATIONS
GENERAL
Earphone Jack: 3.5 mm, disconnects the internal speaker for external earphone,
speaker / microphone, or headset. Also provides cable connection
for PC programming.
Microphone/PTT/Chg Jack: 2.5 mm, for external speaker/microphone, headset or RITRON
model BC-A wall charger
Push Button Controls:On/VolumeUp
Volume Down/Off
PTT
Channel
Speaker Beep Indicators:
On/Volume UP Single beep when radio is turned on, followed by increasing audio
to adjust volume.
Volume Down/Off Decreasing audio to adjust volume, with two tones when unit is
turned off.
Both Volume Buttons Alternates between Tone Squelch (single beep) and Carrier
Squelch (two beeps). If both buttons are held down until the radio
beeps repeatedly, squelch will be disabled.
Channel Number of beeps indicates channel.
RECEIVER
Wide band Model Narrow band Model
Modulation Acceptance: +/- 7.0 KHz +/- 3.75 KHz
Sensitivity (12 dB SINAD): 0.25 µV 0.25 µV
Adjacent Channel (EIA): -60 dB -50 dB
Spurious Rejection: -60 dB -60 dB
Image Rejection (EIA): -70 dB -70 dB
Intermodulation (EIA): -56 dB -57 dB
Noise Squelch Sensitivity: Programmable per channel, factory set for 12 dB SINAD
Frequency Response: 300 - 3000 Hz, de-emphasized
Audio Output 1 Watt into 8 Ω, with less than 5 % THD @ the earphone jack
Receiving System: Dual conversion superheterodyne
I.F. System: 1st - 43.65 MHz 2nd - 450 KHz
L.O. Injection: Low side
QC/DQC Decode Time: per EIA Standards

7
SST-444 SPECIFICATIONS
TRANSMITTER
RF Power Output: Programmable per channel for high or low power
High : 4 Watts (3.5 Watts minimum @ +7.2 VDC)
Low: 1 Watt
Wide Mode Narrow Mode
Emission Designator: 16K0F3E 11K0F3E
Deviation: +/- 5.00 KHz +/- 2.50 KHz
FM Hum and Noise: -43 dB -37 dB
Audio Distortion: < 3 % < 6 %
Spurious and Harmonics: -50 dBc
Audio Response: Meets FCC and EIA requirements
Time-out Timer: 60 seconds, programmable

8
INTRODUCTION
GENERAL
RITRON's SST-444 handheld is a small, programmable two-way radio, designed to operate in the 460-
470 MHz professional FM communications band.
This handheld features push-button operating controls, with the Push-To-Talk and Channel buttons on
one side of the radio. The On / Volume Up and Volume Down / Off, volume and monitor controls are on
top.
Each radio can be “dealer or factory” programmed to contain a unique set of operating frequencies and
options. Selective signaling options include Quiet Call (CTCSS) and Digital Quiet Call (DCS). Transmitter
power, operating bandwidth and battery saver are among the options programmable on a per channel
basis.
Inspection
Each radio package should include a radio, antenna, rechargeable battery pack, belt clip and any optional
accessories ordered. Examine the equipment immediately after delivery and report any damages to your
shipping company.
Model Identification
The SST-444 model, serial number and FCC Identification are displayed on a label located on the back of
the radio beneath the belt clip.
FCC REGULATIONS
Licensing
The FCC requires the radio owner to obtain a station license for his radios before using them to transmit,
but does not require an operating license or permit.
The station licensee is responsible for ensuring that transmitter power; frequency and deviation are within
the limits specified by the station license. The station licensee is also responsible for proper operation and
maintenance of the radio equipment. This includes checking the transmitter frequency and deviation
periodically, using appropriate methods.
Safety Standards
The FCC (with its action in General Docket 79-144, March 13, 1985) has adopted a safety standard for
human exposure to radio frequency electromagnetic energy emitted by FCC regulated equipment.
RITRON follows these safety standards, and recommends that you observe the following guidelines:
•DO NOT hold the radio such that the antenna is very close to or touching exposed parts of the body,
especially the face or eyes, while transmitting. Keep the radio vertical, two to three inches away while
talking into the microphone.
•DO NOT press the Push-To-Talk except when you intend to transmit.
•DO NOT operate radio equipment near electrical blasting caps or in an explosive atmosphere.
•DO NOT allow children to play with any radio equipment that contains a transmitting device.
•Repair of RITRON products should be performed only by RITRON authorized personnel.

9
BATTERY CARE
The handheld is powered by a rechargeable battery, which fits into the radio case (see FIG-1).
CHARGING
The battery pack can lose its charge during storage and shipment, and should be fully charged before the
radio is used. Thereafter, the battery should be charged overnight after each day of use, to ensure peak
radio performance for the next day. Using the cube charger (model BC-A), the battery should charge
completely in 12 hours.
Note: A new battery must be cycled (charged and discharged) several times before it will reach its
maximum charge capacity.
To charge the battery using a RITRON cube charger - plug the charger cord into the smaller of the two
jacks on top of the radio. Then plug the cube into a 110 VAC outlet. The green lamp lights while the
battery is charging, and should go off only when the cube is unplugged.
Two charger contacts, visible through the bottom of the radio case, allow the battery to be charged using
an optional RITRON drop-in charger (model BCPS-FS). The battery pack may be charged inside or
outside of the radio case.
To charge the battery using a drop-in charger (model BCPS-FS) - plug the drop-in charger into a 110 VAC
outlet. Set the portable or battery into the charger. Each battery contact must rest on a charger contact
pin.
Typically, a battery pack’s service life is one year. To ensure maximum service life, follow these
guidelines:
•Do not discharge a battery that is already “run down.” If the battery cannot power your radio, recharge
the battery.
•Do not overcharge a battery. The standard battery should not be left to charge continuously.
•Before storing a battery, charge it for 16 hours. Thereafter, charge the battery for 16 hours once every
30 days.
With daily use and recharging, a battery’s service life is about one year. It is time to purchase a new
battery:
1) When the radio’s transmitter coverage decreases or does not work at all.
2) When the radio quits working after just a few hours of use, even with a full overnight charge.
3) When the battery is more than two years old. The date of manufacture is stamped on every battery.
The first two digits indicate the year, the last two digits the week.

10
BATTERY CARE
BATTERY REPLACEMENT
To take the battery out of the radio, remove the battery door pictured in FIG-1. Use the pull-tab to remove
the battery.
Slide the replacement battery into the radio case. Make sure the spring contacts are inserted between the
battery and paper insulator. The contacts must not touch the radio PC board.
PRECAUTIONS
•Use only RITRON-supplied chargers; other chargers might cause fire, explosion, or other damage to
the radio.
•Do not "fast-charge" a brand new battery pack. Otherwise, the battery might be damaged.
•Once the battery has been charged fully using the normal rate, the fast rate may be used thereafter.
•Do not fast-charge a battery pack that is fully charged. This can shorten battery life.
•Do not charge or replace a battery in an explosive atmosphere. Contact sparking can ignite an
explosion.
•Do not dispose of a battery in fire. An explosion might result.
•Do not charge the battery in temperatures colder than about 45°F. Electrolyte leakage can occur and
ruin the battery.
•Charging in temperatures above approximately 95°F will not harm the battery, but can reduce its
charge capacity.
Fig. 1
Battery Replacement

11
DESCRIPTION OF CONTROLS AND CONNECTORS
Antenna
The flexible antenna radiates and receives radio signals. Before using the radio, be sure the antenna
base is threaded fully into the radio’s antenna bushing.
VHF and UHF antennas are not interchangeable. Use only the antenna type packaged with the radio. A
VHF antenna is pictured in FIG-2. (The UHF antenna is smaller in diameter.)
On/Volume Up
This button switches on the radio, then increases the volume if you continue to press.
Off/Volume Down
This button decreases the volume, then shuts off the radio if you continue to press.
Channel Select
Pressing this button selects the next channel. When the maximum number of channels is reached and
you press this button, the radio resets to channel 1.
Speaker
The speaker allows you to hear calls on your channel.
Push-To-Talk Button
The PTT activates the transmitter, and must be held down while you talk into the microphone. Release
the PTT button to receive.
Microphone
The microphone converts your voice into electrical impulses, which are carried with your broadcast to
receiving radios. Hold the radio about two inches away and talk into the microphone while transmitting.
Shouting does not improve the listener’s reception.
Audio Accessory Jack
This jack connects speaker audio to optional accessories, such as a remote speaker/microphone or an
earphone. For accessories that have a two-plug connector, the smaller plug is inserted into the charge
jack.
This jack is also used to program the radio using the optional PC programming kit.
Charge Jack
The battery may be charged through this jack using a standard RITRON wall socket charger cube.
This jack also connects microphone audio to the optional remote speaker/microphone.
Battery Access (Case Bottom)
The battery door on the case bottom may be removed to access the battery. (Refer to the battery section
of this manual.)
Drop-in Charger Contacts
Two charger contacts in the bottom of the SST-444 radio case allow the battery pack to be charged using
an optional RITRON drop-in charger (model BCPS-FS).
Jack Cover
This rubber cover seals out dust and moisture, etc. Snap the cover into the audio accessory and charge
jack openings when the jacks are not being used.

12
DESCRIPTION OF CONTROLS AND CONNECTORS
CH
ON OFF/HOLD
VOLUME
Belt Clip Installation
If you are going to attach the belt clip to the handheld, follow these instructions:
1) The belt clip is fastened to the radio case back with the Philips head screw provided. Use the screw
included, since a longer screw might damage the radio’s electronics.
Do not use petroleum solvents of any kind on the radio. These can corrode the case.
2) Place the belt clip on top of the radio case back, with the screw hole in the aligned with the hole in the
radio case.
3) Using the screw that came with this accessory, attach the clip to the radio.
Antenna
Vol Down/Off
On/Vol Up
Audio Accessory Jack
Jack Cover
Charge Jack
Speaker
Microphone
Push-to-Talk
Channel Selector
Battery Access Door
(Case bottom) Battery Charger Contacts
(Case bottom)
Fig. 2 Controls and Accessory Connectors

13
OPERATION
On-off/Volume
To switch on the radio - press the on/volume up button.
To adjust the volume - press the volume up button until you reach the desired level. You should hear
noise and any broadcasts on the channel.
To turn off the radio - press and hold the off/volume down button until two tones sound.
To determine whether the radio is on - press the volume down button. If the radio is on, noise or activity
on the channel is heard.
Receive
To hear calls from other users - adjust the volume as desired. The radio can receive broadcasts while the
Push-To-Talk button is not being pressed. Whether or not you hear these broadcasts depends upon the
squelch settings.
There are two types of squelch used in the SST-444 portable. First is carrier squelch. This lets you hear
all broadcasts on your channel strong enough for the radio to detect, and silences noise. Second is one of
the selective signaling or “tone squelch” formats available on the SST-444. This allows you to screen out
“on-channel” broadcasts that do not carry the correct code programmed for the radio.
Note: It is possible that the beginning of a call might be missed while the radio is in battery saver mode. If
this happens, ask the caller to repeat his message.
Monitor
To monitor the channel - press one of the volume control buttons. When you press the volume up or the
volume down button, squelch turns off and all radio traffic on the channel (and noise) sounds in the
speaker.
Selective Signaling Squelch
To activate tone squelch - simultaneously press both of the volume buttons. Hold for a second or two
before releasing. When tone squelch is turned on, the handheld sounds one beep. When carrier squelch
is on, the radio emits a "double beep."
Note: If you continue to hold down the volume buttons after the beep (or double beep), the radio will start
beeping repeatedly. This means that squelch is turned off. Release the buttons. To restore squelch,
press and hold both of the volume buttons until the radio sounds a beep or double beep.
Battery Saver
The handheld has a programmable "battery saver" feature that conserves battery power. The battery
saver constantly checks the radio's transmitter, receiver and controls for activity. If a number of seconds
pass without the receiver detecting a call, and without the user operating a control, this feature removes
power from most of the radio.
During this "off-time," any activity restores full power. Every few fractions of a second, the battery saver
applies power to the receiver, checking for broadcasts. It is possible that the first part of an incoming call
might go unheard before activity is detected and power restored. If this happens, the caller can repeat his
message. Once "radio contact" is made, normal unhurried conversation can follow.

14
OPERATION
Transmit
Normally, you should not transmit until no one is talking on the channel.
To transmit - hold down the Push-To-Talk button and, with the radio a couple of inches away, talk into the
microphone. Speak in a normal tone, since talking louder will not improve the listener’s reception.
Channel Selection
To change channels - press and release the channel button. The radio will beep a number of times equal
to the new channel number. For example, if you select channel 2, the handheld will beep twice. If the
highest channel number is selected and you press the channel button, the radio will reset to channel 1. A
one-channel radio will beep only once when you press the channel button.
WHAT THE RADIO TONES MEAN
The handheld responds to certain instructions by sounding a beep or series of tones. These tones can tell
you whether the radio is working as you expect.
Power On/Self Check “OK”
When the handheld is turned on, it will run a quick “self test.” Once the internal system checks confirm
basic functions, the radio sounds a brief “confirmation tone.” The radio is then ready to use.
Error Tones
However, if the “self test” detects a diagnostic error, an error tone sounds. Alternating tones (the second
is longer and lower pitched) indicate the radio frequency synthesizer is malfunctioning. Turn off the radio
and try again. A long, low-pitched tone means the battery voltage is too low to operate the radio. In this
case, recharge the battery. If you cannot correct a problem, consult an authorized Ritron service facility or
Ritron.
Channel Select
When the channel button is pressed, the radio beeps a number of times equal to the channel number
selected.
Tone Squelch
When you press and hold both Volume buttons at the same time, a single beep will sound to indicate that
tone squelch is on. A "double beep" means that carrier squelch is on.
Recharge Battery Alert
As the battery voltage approaches the minimum required “operating voltage” the radio will emit a short
beep every minute to alert the user that the battery will soon need recharging. Once the battery charge
drops below the required "operating voltage," the radio emits a long, low tone and turns itself off. If you
turn the radio back on, it will beep again and shut itself off. Recharge the battery.

15
OPERATION
OPTIONAL RADIO TONES
The SST-444 can be programmed using the RITRON PC Programmer for optional alert tones.
Receive Squelch Tone
A short tone sounds at the end of each received transmission to indicate that you may transmit.
Busy Channel Transmit Inhibit
If a user is transmitting on your radio frequency without your tone, you will not be allowed to transmit. The
radio will beep a series of long, low tones while the PTT is held down (like a busy signal).
Transmitter Time Out
A low tone followed by a higher-pitched tone sounds and the transmitter automatically shuts off if you hold
down the PTT button longer than the programmed Time-out. The radio automatically switches to receive
mode. Authorized service personnel can turn off this feature.

16
OPERATION
TROUBLESHOOTING
If you have trouble operating the handheld, review the radio controls and operation sections. If you think
the radio is malfunctioning, check the table below.
Problem Possible Solutions
GENERAL
The radio does not work at all. Make sure that the battery is installed correctly, as shown
in FIG-1.
Recharge or replace the battery. (See note 1.)
Operating features do not work exactly The radio has been factory or dealer programmed for
As expected. customized operation.
Reception is poor. Move to a different location. (Note 2.)
Confirm that the proper antenna is connected to the radio.
(See p. 11, "Antenna.")
You cannot hear calls from other radios. Turn off tone squelch. (See Note 3.)
Be certain your radio receives on the same as the caller
transmits. (Note 4.)
Recharge the battery. (Note 1.)
Your calls cannot be heard in other radios. Make sure that your radio transmits on the receive
frequency of the radio(s) you want to call. (Note 4.)
Recharge the battery. (Note 1.)
Battery
The battery loses its charge sooner than Review the battery charging instructions.
expected. Conserve the battery. (Note 5.)
If the radio is used in extreme cold, warm the radio under
your coat. (Note 6.)
Replace the battery. (Note 1.)
Error Tones
An error tone sounds when the radio is first See "Error Tones" in the Operation section.
switched on.
An error tone sounds while you are talking Refer to “Error Tones”
(and the transmitter shuts off).

17
OPERATION
TROUBLESHOOTING
Problem Possible Solutions
Tone Coded Squelch
You cannot screen out calls from users Make sure the channel is programmed with tone squelch.
outside of your tone group. Activate Tone (coded) squelch. (Note 7.)
You cannot hear Tone coded messages Confirm that the channel is programmed to detect the
while in Tone (coded) squelch. same code as the calling radio(s) transmits. (Note 7.)
Others in your tone group cannot hear your Verify that you transmit the same code as the radio(s) you
tone coded messages. call are programmed to detect. (Note 7.)
Notes
1) Try a battery pack from a working radio. If the radio in question works with that pack, the original
battery is suspect. Charge the suspect battery as recommended in this manual. Then, if the charged
original battery cannot power the handheld, try charging again with another charger. If the battery still
doesn’t hold a charge, the pack should probably be replaced. However, if the battery appears to be
good after you try the second charger, the first charger might be faulty. If you think that an accessory
is not operating properly, contact your dealer or RITRON. (Radio accessories come with a 90-day
limited warranty.)
2) Reception can often be improved by moving a short distance. This effect is more noticeable inside of
buildings. The range of these portables equipped with a standard battery pack is about two miles
(line-of-sight).
3) If your radio does not detect calls from other radios on the channel, turn off tone squelch. (Press both
Volume buttons at the same time - a double beep means that tone squelch is off.)
4) If you want to hear a call, you must select a channel that is programmed to receive the caller’s
transmit frequency. If you want to call another unit, you must select a channel that is programmed to
transmit the other radio’s receive frequency. However, if you use a repeater, your channel must be
programmed to work with the repeater’s transmit and receive frequencies. (A radio channel can hold
two separate operating frequencies, one for Receive, the other for Transmit.)
5) Maximum power drain occurs while the radio transmits, so don’t hold down the Push-To-Talk button
more than necessary. Battery power is used while the handheld is left on to receive calls. If practical,
switch off the unit.
6) In extreme cold, a battery’s charge capacity is greatly reduced. If you use the radio in very cold
weather, periodically warm the portable underneath your coat if possible. An optional remote
speaker/microphone would allow you to keep the radio under your coat while transmitting and
receiving.
7) In order for radios to communicate using Quiet Call, they must be programmed with the same tone
code. Each code is unique, and your radio will respond only to the code programmed.
Press and hold both volume buttons at the same time. A single beep means that tone squelch is on.
A double beep means that tone squelch is off.

18
PROGRAMMING THE RADIO
Each SST-444 may be programmed to operate on up to 4 channels. The SST-444 may be programmed
using its Push-to-Talk switch or an optional RITRON programming kit.
PTT (PUSH-TO-TALK) PROGRAMMING allows you to program any channel to one of the radio
frequencies listed in Table 1 and any Quiet Call code listed in Table 2. The radio will transmit and receive
on the programmed table frequency and QC code.
PC PROGRAMMING allows you to program any frequency within the band and channel spacing of the
radio model. This method also lets you customize the handheld with optional operating features.
PTT (PUSH-TO-TALK) PROGRAMMING
Placing the Radio in PTT Programming Mode
1. Turn off the radio by pressing the Volume Down button until the “radio off” prompt sounds.
2. Press and hold the PTT button.
3. While holding the PTT button, press and hold the Volume On button until a rapid beeping is heard in
the speaker.
4. Release the PTT and Volume On buttons. A series of three ascending tones will sound in the speaker
indicating that the radio is in PTT program mode.
Note: If the radio will not enter PTT program mode, this feature has probably been turned off using the
optional PC programming kit.
How to Find Out What Is Already Programmed
1. Place the radio in PTT programming mode as described above.
2. Press the Channel button to select the radio channel you would like to read out.
3. Press the Volume Up button.
4. The radio will sound a series of beeps, pause, and then begin another series. Four series of beeps
will be heard, with each series representing a digit. The number of beeps in a series is equal to the
digit. (10 beeps = the digit 0)
5. Write down each digit while the radio pauses. List the digits in the order that you hear them.
6. The first two digits represent the frequency as shown in Table 1.
7. The second two digits represent the QC (CTCSS) tone frequency as shown in Table 2.
Note: If you are unable to read out a channel, it has probably been programmed using the PC
programming kit to a frequency not contained in Table 1.

19
PROGRAMMING THE RADIO
PTT Programming the Radio
Four valid digits must be entered for the radio to accept PTT programming. The first two digits entered is
the frequency code from Table 1, followed by the two digits for the QC code from Table 2.
1. Place the radio in PTT programming mode as described above.
2. Press the Channel button to select the radio channel you would like to program.
3. Enter the first digit by pressing the PTT button the number of times equal to the digit’s value.
(To enter the digit 0, press the PTT ten times.)
4. Pause after the digit is entered, a tone will sound indicating that the digit has been accepted.
5. Enter the second, third and fourth digits using the same method as the first digit.
6. Press the Volume Up button to enter the new channel programming. The radio will sound a
confirmation tone to indicate that programming has been accepted.
PTT Programming Mistakes
Invalid Entries An error tone means that you tried to save an invalid entry. No programming
changes are made in this case. A triple tone will sound next indicating that the
radio is still in programming mode, and ready for an entry.
PTT Entry Mistakes If you press the PTT five times when you intended four, for example, or if you just
lose count, do not press the Volume Up button to store the entry. Instead, start
over by turning the radio off and placing the radio in programming mode again.
Return To Normal Operation
After you finish programming, turn the radio off and then on again. The radio will beep when it is ready for
normal operation.

20
PROGRAMMING THE RADIO
Table 1 – PTT Programming Frequency Table
Code Frequency Description Code Frequency Description
01 467.7625 J 11 462.6250 Black Dot
02 467.8125 K 12 462.6750 Orange Dot
03 464.5500 Yellow Dot 13 464.3250
04 464.5000 Brown Dot 14 464.8250
05 467.8500 Silver Star 15 469.5000
06 467.8750 Gold Star 16 469.5500
07 467.9000 Red Star 17 463.2625
08 467.9250 Blue Star 18 464.9125
09 469.2625 19 464.6000
10 462.5750 White Dot 20 464.7000
Table 2 – Quiet Call Codes and Frequencies
QC Freq QC Freq QC Freq QC Freq
Code (Hz) Code (Hz) Code (Hz) Code (Hz)
01 67.0 16 114.8 31 192.8 46 189.9
02 71.9 17 118.8 32 203.5 47 196.6
03 74.4 18 123.0 33 210.7 48 199.5
04 77.0 19 127.3 34 218.1 49 206.5
05 79.7 20 131.8 35 225.7 50 229.1
06 82.5 21 136.5 36 233.6 51 254.1
07 85.4 22 141.3 37 241.8
08 88.5 23 146.2 38 250.3
09 91.5 24 151.4 39 69.4
10 94.8 25 156.7 40 159.8
11 97.4 26 162.2 41 165.5
12 100.0 27 167.9 42 171.3
13 103.5 28 173.8 43 177.3
14 107.2 29 179.9 44 No Tone
15 110.9 30 186.2 45 183.5
COMPUTER SOFTWARE COPYRIGHTS
The RITRON, Inc. products described in this manual include copyrighted RITRON, inc. computer
programs. Laws in the United States and other countries grant to RITRON, inc. certain exclusive rights in
its copyrighted computer programs, including the exclusive right to distribute copies of the programs,
make reproductions of the programs, and prepare derivative works based on the programs. Accordingly,
any computer programs contained in RITRON, inc. products may not be copied or reproduced in any
manner without the express written permission of RITRON. The purchase of RITRON, inc. products does
not grant any license or rights under the copyrights or other intellectual property of RITRON, inc., except
for the non-exclusive, royalty fee license to use that arises in the sale of a product, or as addressed in a
written agreement between RITRON, inc. and the purchaser of RITRON, inc. products.