Control Monoprice HDMI Switch #4067 via RS-232

MOTIVATION

The Monoprice HRM-2218F is an automatic HDMI switch that supports RS-232 based control. This program was written to simplify the process of automating the HRM-2218F on Linux.

CREDIT

The mono-switcher program by Anthony Mattera (KernelZechs) helped me to locate the binary protocol, originally reverse engineered by Josh in an Amazon review. I have included the CREDIT.md file (a copy of Josh's Amazon review) which was prepared by Anthony Mattera in this repo for reference.

BUILD INSTRUCTIONS

• This program is intended to be built and run on Linux
• Install a C compiler if one is not present (Run sudo apt install build-essential on Debian distros)
• cd to this repo's directory
• Run make

SYNOPSIS

ctrl_monoprice_4067 <DEVICE> [-i input] [-r retries] [-t ms] [-v]

DESCRIPTION

Simple terminal program to control the HRM-2218F.

DEVICE should be the RS-232 device connected to the HRM-2218F, it will likely be located at /dev/tty*.

This program may return one of three values:

• 0 (Success)
• 1 (Failure)
• 2 (Invalid arguments)

On success this program will output (to stdout) the currently active HDMI input, or zero if no input is active.

Errors and verbose messages are output to stderr.

When changing inputs the currently active input will not change if that input is not currently active, for example:

• Assuming HDMI 1 and 2 are active and the current input is 1 then running:
  ctrl_monoprice_4067 -i 2
  Will output: 2
  However, running:
  ctrl_monoprice_4067 -i 3
  Will output: 1
  

COMMAND-LINE OPTIONS

• -i input
  Set the input, valid range is [1-8]
• -r retries
  Set the number of retries before giving up, valid range is [0-99]
• -t timeout
  Set the timeout (in milliseconds) for calls to read() and write(), valid range is [10-10000]
• -v
  Enable verbose output

LICENSE

This software is licensed under the MIT License.