GTR 225-style COM

The COM-only sibling of the GNC 255 in the style of the GTR 225A: active and standby with station names, MEM for recent and user frequencies, and a FUNC menu with the nearest frequencies and a timer. Comes as COM 1 or COM 2.

Modeled on: Garmin GTR 225A-style COM
Category: Radios and panels
Size: 2 × 1 cells
Version: 1.0 · 2026-10-19
Plan: Pro
Simulators: MSFS 2020 · MSFS 2024 · X-Plane 11 · X-Plane 12

Variants

COM 1v1.0

Tunes and shows COM 1

Picker: RADIO > COM 1

COM 2v1.0

Tunes and shows COM 2

Picker: RADIO > COM 2

Features

Active and standby frequencies with the station on each (e.g. KSLE TWR)
TX while transmitting, RX while receiving, SQ when squelch is open
MEM: the recent frequencies (filled as they are made active), pressed again the user list
FUNC menu: COM lists (RECENT, USER, NEAREST APT / ACC / FSS / WX), ICS, SYS and TMR configuration
ENT stores the standby as a user frequency (up to 15)
Count-up / count-down timer on the bottom line
Holding the swap key puts 121.5 into the active
Display dark without avionics power; dimmed at night, faceplate under the red flood light

On the iPad

Drag the TUNE knob: outer ring MHz, inner knob channel; in menus and lists it scrolls
Tap the swap key to swap active and standby (in a list: the entry straight into the active); hold it for 121.5
Tap COM for the main page, MEM for recent then user frequencies, ICS for the intercom page
Tap FUNC for the menu, ENT to open / load, CLR to back out or clear the timer
Tap MON to toggle the monitor indication (MN); push the COM knob for SQ; drag it for the volume bar

Settings

Which radio: COM 1 or COM 2 (picker variant)
In-unit SYS/ICS pages are shown but have no simulator effect

Keys and controllers

Map any of these to a key, a game controller's button or axis, or a MIDI knob (how):

COM 1 MHz +
COM 1 MHz -
COM 1 channel +
COM 1 channel -
COM 1 swap

Simulator data

What the Hub reads from the simulator for this instrument, and what the instrument sends back. Names are the simulators' own: MSFS SimVars and events, X-Plane datarefs and commands.

Reads

Value	MSFS	X-Plane
COM1 active frequency (kHz)	`COM ACTIVE FREQUENCY:1 (MHz)`	`sim/cockpit2/radios/actuators/com1_frequency_hz_833`
COM1 standby frequency (kHz)	`COM STANDBY FREQUENCY:1 (MHz)`	`sim/cockpit2/radios/actuators/com1_standby_frequency_hz_833`
COM2 active frequency (kHz)	`COM ACTIVE FREQUENCY:2 (MHz)`	`sim/cockpit2/radios/actuators/com2_frequency_hz_833`
COM2 standby frequency (kHz)	`COM STANDBY FREQUENCY:2 (MHz)`	`sim/cockpit2/radios/actuators/com2_standby_frequency_hz_833`
COM transmitting: 1, 2, 0 none (enum)	`COM TRANSMIT:1 (bool)COM TRANSMIT:2 (bool)`	`sim/cockpit2/radios/actuators/audio_com_selection`
COM1 heard (1/0) (bool)	`COM RECEIVE:1 (bool)`	`sim/cockpit2/radios/actuators/audio_selection_com1`
COM2 heard (1/0) (bool)	`COM RECEIVE:2 (bool)`	`sim/cockpit2/radios/actuators/audio_selection_com2`
Aircraft latitude (deg)	`PLANE LATITUDE (degrees)`	`sim/flightmodel/position/latitude`
Aircraft longitude (deg)	`PLANE LONGITUDE (degrees)`	`sim/flightmodel/position/longitude`

Sends

When you…	MSFS	X-Plane
TUNE knob (com1 MHz, com1 + 1 channel), swap (com1 + 2), list entries into the standby; com2 on COM 2	`COM_STBY_RADIO_SET_HZCOM_STBY_RADIO_SWAP`	`sim/cockpit2/radios/actuators/com1_standby_frequency_hz_833sim/radios/com1_standy_flip`

Add-on aircraft with their own systems may use other variables; the Hub reads the standard ones.