K1TMM Radio

Hello and Welcome.

K1TMM Radio

Worldwide Communications.

K1TMM Radio

Local Communications.

If you like our work...

Please, buy us a pizza! (or two!)
Be generous, please


K1TMM CS-750 Codeplug 101 - The Basics

The K1TMM CS-750 Codeplug is set up to get the CT DMR user on the air quickly. It was initially created for K1TMM by AB1JU with contributions and input from system admins and internet research.

Getting Started

Start the CS-750 programming software and open up the file you just saved... Remember to enter your radio ID in the "Unique Radio ID" box and radio name in the "Radio Alias" and "Power on Message (line 2)" boxes under General Settings - Settings. Write the file to your radio... then to save a copy with your radio serial number, read your radio after uploading. We encourage you to customize this codeplug so it works for you.

"Roll Your Own" DMR

The following is pretty specific to the K1TMM CS-750 codeplug, but the concepts are similar to the CS700 radio and applicable to other DMR radios. Here are some of the features and items that we hope will enhance your CT System DMR experience. Feel free to tailor things to your own needs.


A zone is a grouping of channels.  The CS750 radio has a 16 stop channel selector, so there are a maximum of 16 channels you can have in each zone.  In the K1TMM codeplug, each repeater has its own individual zone, with all the talkgroups that are carried for that repeater; plus a monitor all channel. The other types of zones are listed below.

ARES Zones

Each ARES repeater has an additional zone with just the ARES talkgroups. All CT ARES repeater channels also monitor CT Statewide and the CT‐ALERT talkgroups.

Talkgroup Zones

The talkgroup zones contain all repeaters that contain the listed talkgroup. This can be used while traveling to monitor or to maintain a conversation on one talkgroup. Each zone also includes a monitor all channel which can be used to talk back to the last heard repeater if you press the PTT within 7 seconds of the last transmission. These zones will be added to the codeplug in a future version.

Area Zones

The Area zones comprise 2 or 3 repeater systems with the talkgroups North America (NA), WorldWide English (WW Eng), North East (NEast), TAC 310 and Local. (NY / NJ Area repeaters replace Local with NY‐NJ Trbo.) There is also a Monitor All channel; this channel also scans 441.000 simplex. The Monitor All channel can also be used to talk back to the last repeater / talkgroup heard if the PTT is pressed within 7 seconds of the last transmission. These zones will be added to the codeplug in a future version.


This is where all the details such as frequency, talkaround, admit criteria, color code, scan list, group list, timeslot, etc. are placed. Some of these parameters can be different if the same channel is in different zones. For example, in the standard zone you may want to use a Group List to hear other timeslot traffic, but in your "ARES Zone" you might use a different Group List so that other talkgroups are heard. There are lots of possibilities for customization here.

Button Definitions

There are 3 programmable buttons on the CS-750, each with two functions depending on how long it is held down. These functions are defined under "General Settings - Buttons". The K1TMM CS-750 button functions are:

  • Top Button Short: Emergency On (this triggers on simplex 441.000 only)
  • Top Button Long: Emergency Off
  • Side Button 1 Short: Zone Up
  • Side Button 1 Long: Toggle Scan On / Off
  • Side Button 2 Short: Zone Down
  • Side Button 2 Long: Monitor

Text Messages

These are the "Quick Text" messages you find under the "Messages" icon. They are for text you send frequently, such as "Please meet me on Local".

Digital Contact

This is the most dynamic part of the codeplug as here you find the radio ID aliases (Private Calls) and talkgroup numbers (Group Calls). As more folks get involved in DMR, more contacts are added to the list. You can add contacts too, not only new radio IDs, but also new talkgroups. So if one of your DMR repeaters starts carrying a new talkgroup, you can add that in here. The "Contact Name" is what appears on the screen, "Call Type" is "Private" for a radio ID and "Group" for a talkgroup, with "Call ID" being either the radio ID or talkgroup number.

Digital RX Group Calls (Group Lists)

These work together with your channels let you listen to more than one talkgroup at a time; here is how it works. Each channel can have a Group List. Each Group List contains Group Calls from the Digital Contacts list. The Group List gives us a way to monitor more than one talkgroup when you are on a channel. The practical result is similar to scanning the talkgroups listed in the Group List. In the K1TMM CS-750 codeplug, we have several Group Lists such as TS1 All, TS2 All, TS1-A All and TS2-A All. Take a look at the Monitor All channel for each DMR repeater and you will see each has a Group List assigned. The Group List corresponds to the talkgroups that you will hear while on that channel. It also auto-scans the scanlist which includes the MA1 channel - this allows you to monitor the talkgroups that are in the Group List that is assigned to the MA1 channel as well - see "Scanning all traffic on a repeater" below.  When you select the Monitor All channel in a Zone, you will hear (and be able to reply to) traffic on the listed talkgroups for that repeater, both the ones listed in the Monitor All channel group list and the ones listed in the MA1 channel group list. Another example: Each ARES channel uses a group list so that it will not only listen to its indicated talkgroup, but it will also monitor the CT Alerts group list talkgroups too.

Practical DMR

Scanning all traffic on a repeater

Remember the "TS1 All" and "TS2 All" Group Lists? Here is where they fit in the K1TMM codeplug. The TS1 All Group List has all the talkgroups that are on timeslot 1 and the TS2 All Group List has all of the talkgroups that are on timeslot 2. We have set up two channels for each repeater, "MA1" using the Slot 1 Group List and "Monitor All" using the Slot 2 Group List. In the repeater Scan List we have these two channels: [repeater] MA1 and [repeater] Monitor All. When we go to the "Monitor All" channel, it scans this list; it listens to all of the timeslot 1 traffic, then to all the timeslot 2 traffic. Much better than going thru each individual channel. Each repeater has this feature. But how do you reply to a call? In the "General Settings" we have Group Call Hang Time is set to 7 seconds (7000) to give us 7 seconds to reply. "TX Designated Channel" is set to "Last Active" so that when we key up within 7 seconds, we are on the last channel we heard. We have also set "Priority Channel" to "None" since we want to give all channels an equal opportunity to be heard.

Custom Scan Lists (This feature will be added in a future version.)

The K1TMM CS-750 codeplug has custom scan lists: each Area Zone and Travel Zone has a corresponding scan list. The Area Zone scan lists will scan the North America (NA), WorldWide English (WW Eng), North East (NEast), TAC 310 and Local talkgroups. (NY / NJ Area repeaters replace Local with NY‐NJ Trbo). Each Area Zone has 2 or 3 repeaters that it will listen to. You will only hear traffic from the repeater you are in range of... sort of a "poor man's roaming".  Setting your radio to an Area Zone and putting it on the Monitor All channel, especially while driving, will enable you to monitor that group of repeaters and talkgroups without constantly changing the radio settings.  Each Travel Zone scan list has up to 15 repeaters all on one talkgroup that it scans.  Putting your radio on the Monitor All channel of a Travel Zone will allow you to travel throughout that portion of the state and maintain a conversation on that talkgroup.

Talkaround and Simplex

For those that are used to being able to use talkaround on a repeater output, yes, you can do that in the DMR world too.  However, talkaround in the DMR world is really not recommended. Simplex or your Local talkgroup is a much better choice, and the K1TMM CT codeplug does have a simplex zone that contains all the suggested simplex channels.

The suggested simplex channels for UHF DMR are:

441.0000 99 1 1
446.5000 99 1 1
446.0750 99 1 1
433.4500 99 1 1


We hope you find our codeplug useful and a good starting point...  Feel free to post questions on the K1TMM forum so that the answer will benefit everyone!

Remember: Amateur Radio is all about experimentation and learning, so we encourage you to customize this codeplug so it works for you.


If you like our work...

Please, buy us a pizza! (or two!)
Be generous, please


Forum Login



Search in QRZ.COM


Solar X-rays:
Status Offline
Geomagnetic field:
Status Offline

Solar Data

Towel Day - Don't Panic

Copyright © 2006-2020 K1TMM. All Rights Reserved.