I just got a pair of Midland GXT800VP4 radios. We’re new to privacy codes and I don’t understand. How do I set them up and which ones do I use? Is it just random? I have NO knowledge of 2 way radios, other than to just choose a channel and talk. I plan on getting the license, but want to learn how to operate the things first. The instructions don’t really explain what to do. Could anyone help me?
When you use a “privacy code”, your radio is actually attaching an inaudible tone to every transmission that you send. Incoming transmissions are filtered, and only those that have the right tone attached are allowed through. Each numbered privacy code within the radio (142 for the Midland GXT800VP4) represents a distinct tone.
Privacy codes are called many different things in the radio world. Other popular names are PL (private line) codes, QT/DQT (QuietTalk/Digital QuietTalk) codes, Interference Eliminator codes, Sub-channels, CTCSS, DCS, and probably a few more that I’m not thinking of. “Privacy codes” seems to be the name that has stuck among consumer radios, but it (along with sub-channels) is probably the most inappropriate. The use of these codes doesn’t give you any additional privacy, it simply screens out the chatter from others that might be using the same frequency as you. This could give you the perception that you are the only one using the frequency, but in reality, anyone around you could still hear you simply by setting their radio to not filter for a “privacy code”.
That concludes my history lesson, now on to your problem 
Right out of the box, your Midland radios are set to use analog privacy code (CTCSS) 1. I don’t think you have a need to change this, unless you start hearing unwanted transmissions from people you don’t know. Even if that happens, a better option may be to go to a different channel.
If you decide you want to change to a different code, it doesn’t matter which one you choose. The only thing that is important is that all of your radios are set to the same code. Here are the instructions from the manual for changing the privacy code. Note that instead of giving you a simple 1-142 choice, they break the codes down into analog (CTCSS) 1-38 and digital (DCS) 1-104. This adds an extra step.
To select a Privacy Code for the current channel press the MENU
button twice, and then the buttons to select between “Off/CTCSS/
DCS”. Press again the MENU button and the (up/down arrow) button to select one of the 38 CTCSS Codes or one of the 104 DCS Codes.
The Privacy Code icon on the display will indicate whether you set
your Privacy Code in CTCSS or DCS mode. To confirm the selection,
press the PTT button or press MENU button again to move to the next
feature setting.
Note : If you select any CTCSS Privacy Code, any pre-selected
DCS Privacy Code will be cancelled and vice-versa.
Selecting a Privacy Code of “oF” will disable the Privacy
feature. To communicate between two GXT800/808/850
Series radios, all radios in your group must be set to the
same channel and Privacy Code selections.
Thanks, I’ve got it now.
Just so I have this straight. So if I’m using a ctss or dcs privacy code with my radios on say a frequency of: 144.100 who can pick up my transmission? If someone else is tuned to that frequency they would still be able to hear my transmissions would they not?
These privacy codes really only filter out other transmissions incoming to my radios right? Is this correct?
You are correct. There is no privacy. They just limit what you can hear. Other can hear everything.