DTMF Call IDs

Many GMRS radios have a feature called a DTMF call ID (also known as ANI — Automatic Number Identification, or PTT ID). When enabled, your radio automatically sends a short burst of DTMF tones every time you key up or unkey. This tone sequence acts as a caller ID, letting others know who's transmitting.

How it works

You program a short numeric code (typically 3–6 digits) into your radio's settings. When you press PTT, the radio rapidly sends that code as a series of audible DTMF tones — the same touch-tone sounds you'd hear dialing a phone number, just played very quickly. Other radios that support DTMF decoding can display this code on their screen, identifying who called.

Most radios let you choose when the ID is sent:

• BOT (Beginning of Transmission): the tone burst plays right when you key up, before you start talking
• EOT (End of Transmission): the tone burst plays when you release PTT, after you finish talking
• Both: sends the ID at the beginning and end of each transmission

What it's used for

• Identification: lets people on the channel see who's calling without having to recognize your voice. Handy on busy channels or when working with people you don't talk to often
• Logging: some repeater controllers and base stations can log DTMF IDs, keeping a record of who used the channel and when
• Selective calling: some radios can be set to only open squelch when they receive a specific DTMF code, essentially creating a private call within a shared channel

Setting it up

The exact steps vary by radio, but the general process is:

1. Go into your radio's menu and find the DTMF or PTT ID settings
2. Enter your desired code (a short number you'll use as your ID)
3. Choose when to send it — BOT, EOT, or both
4. Enable the feature

There's no central registry for DTMF call IDs on GMRS — you just pick a number and use it. If you're part of a group or repeater community, the group may coordinate IDs to avoid duplicates.