Choosing a Channel
Your radio has 22 channels and 38 CTCSS codes
you can use to talk to others. In order to speak to
someone, each of you must set to the same
channel and CTCSS code.
To choose a channel:
With the radio in "Normal" operating mode press the
ch
key and press the
▲
or
▼
key to increase or decrease
the channel number displayed.
Note:
FRS channels 8-14 have an expectancy
range of up to 2 miles. GMRS channels 1-7, 15-22
have an expectancy range of up to 6 miles.
You can know which GMRS or FRS channel is
active by the icon. The
icon indicates GMRS
channel, and the
icon indicates FRS channel.
GMR638-2
GMR638-2CK
GMR638-3CK
*Range may vary depending on environmental and/or topographical conditions.
• 15 GMRS / 7 FRS Channels
• 38 CTCSS Codes
• Up to 6 Mile Range*
• Internal VOX Circuitry
• 5 Selectable Call Tone Alerts
• Backlit LCD Display
• Optional Headset Accessories
• Headset Jack
• Roger Beep
1
Antenna
2
PTT (Push-To-Talk) Button
3
Monitor Key
4
Call Key
5
Scan Key
6
Channel Key
7
Speaker
8
Headset Jack
9
On/Off/Select Key
10 Volume Up (Default)/
Channel Up Key
11 Volume Down (Default)/
Channel Down Key
12 Microphone
13 Battery Level Meter
14 Receive Indicator
15 Call Indicator
16 Scan Indicator
17 Channel Indicator
18 Transmit Indicator
19 Volume Setting Indicator
20 VOX Indicator
21 GMRS/FRS Indicator
22 Keypad Lock Indicator
23 CTCSS Indicator
24 Charging LEDs
25 Charging Contacts
Congratulations on your purchase of the Uniden
GMR638 Series (General Mobile Radio Service)
radio. This product is a lightweight, palm-sized
radio. Use it at sporting events to stay in contact
with family and friends, hiking, skiing, outdoors, or
in a neighborhood watch for vital communication.
This compact, state-of-the-art device is equipped
with many features.
PACKAGE CONTENTS
Depending on the model configuration, your
package should include:
GMR638-2
Two GMR638 Radios with Belt Clips
GMR638-2CK
Two GMR638 Radios with Belt Clips
One Dual Charging Cradle (RC6338)
Two Rechargeable Batteries (BP38)
One AC Adapter (AD-0001)
GMR638-3CK
Three GMR638 Radios with Belt Clips
One Dual Charging Cradle (RC6338)
One Single Charging Cradle (RC6488)
Three Rechargeable Batteries (BP38)
Two AC Adapters (AD-0001)
The following optional accessories may be
purchased by calling the Customer Hotline at
1-800-297-1023 (Mon-Fri 7 am to 7 pm,
Sat/Sun/holidays--except Thanksgiving and
Christmas--9 am to 5 pm, CST).
Use only Uniden accessories.
• NiMH Battery Pack - #BP38
• Charging Cradle - #RC6338 or RC6488
• Headset - #HS2467
• AC Adapter (AD-0001)
GMRS LICENSE
The GMR638 radio operates on the General
Mobile Radio Service (GMRS) frequencies when
using Channels 1-7 and channels 15-22. You
must have a GMRS license issued by the Federal
Communications Commission to legally use
these channels. For licensing information and
application forms, visit the FCC online at:
www.fcc.gov/wtb/uls or call the FCC hotline at
1-800-418-3676. If you have any questions, you
can contact the FCC direct at 1-888-225-5322.
No license is required for operation on channels
8-14 or operation on any channel in Canada.
INSTALL THE BATTERY
Each GMR638 radio uses a NiMH battery pack (not
included with GMR638-2) or 4 AAA alkaline batter-
ies (not included). If you use alkaline batteries, we
recommend high quality alkaline batteries.
To install the NiMH battery pack:
1) Make sure your radio is OFF.
2) Release the battery cover clip, then remove the
battery cover.
3) Install the NiMH battery pack into the battery
compartment. Be certain to follow the instruction
written on the label on the battery pack.
Installing the battery pack incorrectly will prevent
the unit from operating.
4) Align the battery cover tabs with the GMR638
tab holes then replace the cover clip.
USING THE RADIO
In order to get the most out of your new radio, read this
reference guide completely before attempting to operate
the unit.
Turning the Radio On and Adjusting the Volume
1) Press and hold the
sel/
key to turn the radio ON,
and increase the speaker volume by pressing the
▲
key. To decrease the volume, press the
▼
key.
2) Press and hold the
sel/
key again to turn the radio
OFF.
Adjusting the Sound (Key Beeps)
Your radio emits a beep each time one of the keys
(except for the
PTT
button, and
call
key) is pressed.
To turn this sound OFF, press and hold the
call
key while
turning ON the radio. Repeat this step to turn the sound ON.
Navigating through the Menu
To access the advanced features of the
GMR638, your radio has a Menu function.
• Battery Charger
• Battery Level Meter
• Channel Monitor
• Channel Scan
• Keypad Lock
• Key Beep
BATTERY LEVEL AND
LOW BATTERY ALERT
This unit has a battery level meter on the display to
indicate the status of the batteries. When the battery in the
unit is low, the battery level meter icon
will flash.
Recharge the NiMH battery pack immediately or if you are
using the alkaline batteries, you must replace the alkaline
batteries in order to continue using the radio.
Warning!
To avoid the risk of personal injury or property
damage from fire or electrical shock, only use the Uniden
accessories specifically designated for this product.
1) To enter the Menu, press the
sel/
key.
2) Additional presses of the
sel/
key will advance
you through the Menu until exiting to "Normal"
operating mode.
3) Other methods of exiting the Menu function are:
a. Press and hold the
sel/
key again.
b. Press the
PTT
button,
mon
,
call
,
scn
, or
ch
key.
c. Wait 10 seconds until the unit automatically returns to
“Normal” mode.
Choosing a CTCSS Code
Each of the channels 1-22 may have any one of
the codes, OFF or 1-38 selected. Code
oF
(OFF)
indicates no CTCSS code selected and your radio
can receive a signal regardless of the code settings
of the transmitting radio.
1) Enter the Menu. The CTCSS code on the LCD
display will appear.
2) Press the
▲
or
▼
key to increase or decrease
the code number displayed. You can also select
oF
(OFF) at this stage.
3) Exit the Menu.
Talking on Your Radio
To talk to others using the radio:
1) Press and hold the
PTT
button and speak in a
clear, normal voice about 2-3 inches away from
the microphone. While you are transmitting, the
icon will appear on the display. To avoid
cutting off the first part of your transmission,
pause slightly after pressing the
PTT
button
before you start talking.
2) When you have finished speaking, release the
PTT
button. You can now receive incoming calls.
While receiving, the
icon will appear on the
display.
Voice Operated Transmission
Your GMR638 radio is equipped with a user
selectable Voice Operated Transmitter (VOX) that
can be used for automatic voice transmissions. The
VOX feature is designed to be used with a headset
with a microphone. Transmission is initiated by
speaking into the remote microphone instead of
pushing the
PTT
button.
To select the VOX level:
1) Enter the Menu. Advance through the Menu until
the
vox
icon appears on the display. The current
level (OFF, 1-3) will be indicated. Level
oF
(OFF)
disables VOX, while levels
-
set the
sensitivity of the VOX circuit.
2) Press either the
▲
or
▼
key to the desired VOX
sensitivity level. Use level 1 for increased
sensitivity to voice in normally quiet
environments, and use a higher level to reduce
undesired activation in very noisy environments.
3) Exit the Menu.
Transmitting a Call Tone
Your GMR638 radio is equipped with 5 selectable
call tones that will be transmitted when the
call
key
is pressed.
To select a call tone:
1) Enter the Menu. Advance through the Menu until
the
call
icon is shown on the display. The current
call tone number (
-
) will be indicated.
2) Press the
▲
or
▼
key to increase or decrease
the number to the desired call tone. Each tone
will be heard through the speaker.
Normal
Normal
CTCSS
VOX Level
Call Tone
Key Lock
1-5
OFF, 1-38
OFF, 1-3
ON-OFF
GMR638 RADIO
USING THE CHARGING CRADLE
You can use a charging cradle to recharge the BP38
batteries in your GMR638.
GMR638-2CK and GMR638-3CK includes charging
cradle(s). Follow these
instructions to recharge the radios in a charging
cradle.
Make sure to turn the radio OFF before placing
the radio in the charging cradle. Otherwise the
battery level meter icon won’t indicate properly.
1) Connect the AC adapter (# AD-0001) to DC IN
9V jack and to a standard 120V AC wall outlet.
2) Set the charging cradle on the desk or tabletop,
and place the radio in the charging cradle with
the keypad facing forward.
3) Make sure that the LED illuminates. Charge the
battery pack for 16 hours and remove the radio
from the charging cradle after charge.
Note:
Always make sure your battery pack is fully
discharged before recharging to prolong the life of
the battery pack. The LED will illuminate while the
radio is in the charging cradle.
3) Exit the Menu.
To transmit the selected call tone, press the
call
key. The selected tone will automatically be
transmitted for a fixed length of time. Call Tone will
be cancelled when the
PTT
button is pressed.
Channel Scan Feature
Your GMR638 radio has a channel scan feature
that allows you to easily scan all 22 channels.
When an active channel is detected, the radio will
pause on that channel until the channel is clear.
Then after a 2 second delay, the radio will continue
scanning. Pressing the
PTT
button while the scan
is paused on a channel will allow you to transmit on
that channel.
To turn ON channel scan:
Press the
scn
key the
scan...
icon is displayed.
The channel number on the display will change as
the radio rapidly cycles through the channels.
To turn OFF channel Scan:
Press the
sel/
,
call
key, and
PTT
button or press
the
scn
key.
Key Lock
To lock the keypad:
1) Enter the Menu. Advance through the Menu until
the
icon appears on the display. The current
Key Lock status
oF
(OFF) blinks on the display.
2) To switch the Key Lock mode from
oF
(OFF) to
on
, press the
▲
key.
3) To confirm the setting, press the
sel/
key.
The radio returns to the "Normal" mode.
Note:
If you exit the setting mode before confirming
your selection by pressing the
sel/
key, the Key
Lock setting will be set to
oF
(OFF)
.
To unlock the keypad:
1) Press and hold the
sel/
key to turn the radio
OFF.
2) Press and hold the
sel/
key again to turn the
radio ON. The keypad is unlocked.
Automatic Power Save Feature
Your GMR638 radio has a unique circuit designed
to dramatically extend the life of the batteries. If
there is no transmission nor an incoming call within
3 seconds, your radio switches to the Power Save
mode. The radio is still able to receive transmis-
sions in this mode.
LCD Backlight
The LCD Backlight will automatically turn ON when
any key (except the
PTT
button is pressed. The
LCD display will illuminate for 10 seconds before
turning OFF.
Note:
The charge indicator LEDs will remain on as
long as the radios are left in the charger.
