11
Operational Hints
This table lists codes adopted by the Associ-
ated Public Safety Communications Officers
(APCO).
Note: Although this table lists the 10-codes’
meanings in the form of a statement, they
can also be phrased as questions (10-6: Are
you busy?, 10-20: What is your location?).
MAXIMUM RANGE
The maximum range and quality of CB radio
transmissions vary depending on the follow-
ing conditions:
• the type and quality of antenna used
• the height of the antenna’s mounting
location — the higher the antenna, the
better the signal’s range
• the surrounding terrain — mountains
and tall buildings limit the range
• weather conditions
• the number of nearby radios operating
on the same channel
• standing wave ratio (SWR) between the
antenna and the CB
Code
Meaning
10-1
Your signal is bad.
10-2
Your signal is good.
10-3
Stop transmitting.
10-4
Message received and under-
stood.
10-5
Relay information to _____.
10-6
I am busy or are you busy?
10-7
Out of service.
10-8
In service.
10-9
Repeat last message.
10-10
Negative (NO).
10-11
_____ in service.
10-12
Stand by.
10-13
Report road/weather condi-
tions.
10-14
Information.
10-15
Message delivered.
10-16
Reply to message.
10-17
En route.
10-18
Urgent.
10-19
Contact _____.
10-20
What is your location?
10-21
Call _____ by telephone.
10-22
Cancel last message.
10-23
Arrived at the scene.
10-24
Assignment complete.
10-25
Meet _____.
10-26
Estimated time of arrival is
_____.
10-30
Use caution.
10-31
Pick up.
10-33
Emergency traffic. Clear the
channel.
10-34
What time is it?
10-41
Switch to Channel xx.
10-62
Cannot understand.
Code
Meaning
21-1705.fm Page 11 Thursday, September 7, 2000 10:41 AM