RS-422 port on the H.264 Encoder

Forgive my ignorance, but I'm wondering what the 9 pin serial port is used for on the BMD H.264 Encoder. I know it's for the Sony Deck Control protocol, but that's about it. Can I send commands to the Encoder that will trigger Desktop Video to start capturing? Or does it serve some other purpose?

It is only used by Media Express to trigger play/stop command when you select record. Useful for encoding from HyperDeck (or other device) as source.

The encoder itself doesn't start the recording, it is up to the software to do this.
MX-Light is a good application that allows remote network commands to trigger recording from the encoder.
http://mxlight.co.uk/rc-ip.html