I have a situation with an MRX-1 where I will have more than 2 RS-232 devices. Probably 4 total. But only 2 RS-232 ports on the MRX1. Assuming I cannot get an MSC-400 in here, I have heard that there are ways to use RS-232 "splitter" to allow 2 disparate devices to share a single RS-232 connection. As long as they are wholly different devices, which they will be, the opposite device should simply ignore the commands that it cannot understand, leaving the commands to be listened to properly by the device that DOES understand them. So, the question is cabling...I have found several sites that sell a "splitter" or "Y cable" such as this one:

[Link: monoprice.com]

or this one:

[Link: cnc-specialty-store.com]

Are these devices the right move for situations like this?

Thanks for the help,
Brian