SL40-style COM

A COM radio in the style of the SL40, its 16-character amber LED line showing the active and standby. EC puts 121.50 in the standby, RCL recalls nearby, recent, memory and weather frequencies, MEM stores the standby. Comes as COM 1 or COM 2.

Modeled on: Garmin (Apollo) SL40-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

Amber LED dot-matrix line: the active, then s (m while monitored) and the standby
TX under the active while transmitting on that COM
EC: 121.50 into the standby, monitored
RCL lists: REM (airports around), LST (last 8 active), MEM (your 8), WTH (weather channels); ident and frequency alternate
MEM stores the standby ('Done', or 'mem full' at 8)
Green LEDs over MON and RCL when on
System pages via MON held (display only)
Display dark without avionics power; dimmed at night, faceplate under the red flood light

On the iPad

Drag the dual knob: outer MHz, inner channel; in RCL outer picks the list, inner the entry; in the system pages it scrolls
Tap the swap key, or push the dual knob, to swap active and standby (loads the recalled entry first)
Tap EC for 121.50 in the standby
Tap MON to toggle monitoring the standby; hold it for the system pages (tap to leave)
Tap RCL to open the lists; RCL again loads the entry into the standby
Tap MEM to store the standby

Settings

Which radio: COM 1 or COM 2 (picker variant)

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`
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
Dual knob (MHz / channel), swap or knob push, EC and RCL entries tuned 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.