[THEOS] Transmitter (DBTX) - Buttons, Antennas, Battery & Setup

This guide covers the physical setup of your THEOS DBTX bodypack transmitter: what each button does, how to install the antenna and lavalier microphone, how to load the battery and microSD card, how to read your recordings, how to attach the belt clip, and what the front LED indicators mean.

Button Functions

DBTX front panel with Down, Up, ON/OFF/Back, and OK/MENU buttons labeled

ON/OFF/Back Button: Long press to turn the DBTX on and off. It also functions as a Back button while navigating the menus and setup screens, returning you to the previous screen or menu item.
Up / Down Buttons: Used to select options and adjust values on the setup screens. Long press Up to enter the recording interface. Long press Down to enter the timecode setting interface.
OK/MENU Button: Enters the menu and selects the highlighted item.

For a full walkthrough of every menu screen these buttons reach, see [THEOS] Transmitter (DBTX) Menu Reference.

Antenna Installation

DBTX whip antenna and SMA connector, showing rotate-to-tighten direction

Rotate the matching antenna onto the antenna socket on the upper part of the DBTX, then tighten it to complete the installation.

The DBTX antenna is a whip antenna with an SMA interface.

Lavalier Microphone Installation

Lavalier microphone connector being screwed into the DBTX 3.5mm TRS input

The DBTX has a locking 3.5mm TRS connection. Clip the lavalier microphone onto your clothing, then screw its connector into the DBTX TRS microphone input so it cannot pull loose during a take.

Battery Installation

Pressing the lock keys on both sides of the DBTX to open the battery compartment and insert an AA battery

Press the battery compartment lock/unlock keys on both sides of the DBTX at the same time, then open the battery compartment cover.

Install the AA battery into the compartment in the correct direction (match the + and - markings).

Insert and Replace the microSD Card

microSD card slot at the top of the DBTX battery compartment, with a USB-C cable connected

The microSD card slot sits at the upper part of the DBTX battery compartment. Open the battery compartment cover and insert the microSD card directly into the card slot before installing the AA battery.

If the battery is already installed, remove it first to reach the card slot.

Read the Audio Files

You can power the DBTX from the included USB-C to USB-C cable connected to a DC adapter (adapter not included). To read and download the audio files from the microSD card through the USB-C port, go to the main interface, enter SYSTEM, and select READER mode.

To learn how the DBTX records to the card, see [THEOS] Recording Modes.

Installation of the Belt Clip

Belt clip aligned with and inserted into the installation holes on both sides of the DBTX

Align the belt clip with the installation holes on both sides of the DBTX and insert it until it seats into place.

LED Indicator Definitions

DBTX front indicators labeled REC Indicator, POWER Indicator, and AUDIO Indicator

Three LEDs across the top of the DBTX front panel report its status at a glance.

Indicator	What it means
REC	Stays red while the DBTX is recording.
POWER	Glows green when the battery is good and turns red when about 30 minutes of operation remain.
AUDIO (volume)	Changes brightness and color with the current level on the screen meter. Green from -40dB to -10dB, red from -10dB to 0dB. When the microphone is muted, the red light flashes slowly.

To set your levels so the AUDIO indicator sits in the green, see [THEOS] Gain Staging.