[tech] Vending machine changes

[David Adam]

A bunch of changes to the setup of the vending machines in the last couple 
of weeks, mostly to support the integration of the MIFARE reader.

Instead of using the wall cabling, there's a CAT5 cable over the wall (the 
wall cabling, which terminates at 22 on the patch panel, is shorted out 
somehow).

That CAT5 cable has a Serial Duplex Harness, Mk. Tearle, on either end. 
It connects the snack machine to Martello's /dev/ttyS1, and the MIFARE 
reader to /dev/ttyS0. 

The MIFARE reader itself is powered using a PS/2 connector attached to a 
5V power supply, which is itself attached to a 110V source inside the 
snack machine.

Thanks to [MTL], [NTU] and [LGM] for the hardware work.

David Adam
UCC Wheel Member
zanchey at ucc.gu.uwa.edu.au