I figured it out after downloading a set of RS232 codes off this site. What I needed to do was to send the command in ASCII format, followed by a carriage return. The command ended up being: sw1 A\x0D

I hope that helps someone in the future. It also helps me to recommend the Tripp Lite B126-4x4 as an excellent value for HDMI switching and extending over a single CAT5e/CAT6 cable.