Call Disconnect Function in Digital Two-Way Radios

The call disconnect (Call Interruption) function is featured as a standout capability on the NX-1300 and NX-1200 series for digital protocols such as DMR. As described, the feature allows one two-way radio to “interrupt” an ongoing transmission on the same channel by sending an interruption request to the device that is currently transmitting.

Why this function matters

  • In digital radio systems (such as DMR Tier II) used in industry, security, transportation, or rescue operations, urgent situations can arise in which another user needs to insert their call into a channel that is already in use. The Call Interruption function makes this possible, ensuring that critical information is not delayed.

  • When you design or operate a DMR repeater (as with NX-1300 + NXR-1800E2), understanding and properly configuring this function improves channel management: it avoids channel congestion, prioritizes urgent communication, and adds flexibility to the system.

How it works

The basic steps are as follows:

  1. Device A is talking — transmitting a call (Group or Individual) on the DMR channel.

  2. Device B needs to make an emergency call or has higher priority: B presses a button programmed as “Call Interruption” (a PF button) or a PTT button configured for “Interrupt CALL” while a call is in progress.

  3. Device B sends an interruption request message to device A, which is currently transmitting.

  4. Device A receives the request and is interrupted — A’s current transmission ends immediately, and device B can start transmitting.

Benefits & real-world applications

  • Prioritizing emergency communication: In construction-site management, rescue operations, or large events, when an incident occurs, the manager or dispatch center needs the ability to “break in” on the current call to broadcast an emergency announcement immediately.

  • Effective channel management: When the channel is occupied by a less critical call, a device with priority can interrupt it for an urgent task — avoiding the need to change channels or wait.

  • Integration in repeater / digital radio systems: When you operate a DMR repeater handling multiple slots, this function lets you set clear priority policies — for example, when a control station or priority radio transmits, regular calls are interrupted.

Conclusion

The Call Interruption function on digital two-way radios is a powerful tool that makes digital communication systems more flexible, prioritized, and reliable. For the requirements you currently have — particularly DMR repeaters in professional two-way radio environments — understanding and applying this feature is a major advantage.