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How do I deregister my TL7600 Marathon mic from from an AT&T DECT 6.0 phone?*

Hello again, friends! Old mic dead? Old mic needed for another phone or Marathon base? Let’s deregister it from that old AT&T phone! It’s time the drop the mic!

AT&T Marathon Mic

1) From the AT&T telephone base, press and hold the FLASH button until the screen says “DEREGISTER ALL HEADSETS”

2) Select Yes!

3) The screen on the telephone base will then say “Please Wait” for up to 1 minute.

4) When it is finished, it will switch back to the regular screen display and your AT&T mic will be deregistered (it will show orange and blue on the on/off light).


This has also deregistered your cordless extensions! Oh no!

1) FIRST register the Marathon mic to wherever it’s going. New phone, Marathon TL7610 base, etc.

2) THEN gather your cordless phones and set them right next to the AT&T telephone base.

3) On the base of the telephone, find one of the following buttons:

*Handset Locator



(Proceed to Step 4a for Handset Locator and Hold buttons. Proceed to Step 4b for Menu button)

4a) If you see HANDSET LOCATOR or HOLD button, then press and hold this button until the phone says, “REGISTERING, PLEASE WAIT.”

4b) If there is a MENU button, press MENU then go to Settings, then Registration. Then press Menu again to select Registration. Sometimes there will not be a “Settings” it will just have “Registration” as one of the main menu options. The telephone will say “REGISTERING, PLEASE WAIT” once Registration is selected

5) Once the telephone says “REGISTERING, PLEASE WAIT,” press the # button on each cordless extension. It will also display “REGISTERING.” Then just wait! The cordless extensions will register back to the AT&T telephone base!

Hi, I'm Kyle!

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Kyle Newgent
Headset Blogger