Riaan wrote
a certain guitar that's for sale.
A Godin SA or a Brian Moore? (EDIT: OK I read further and see it's a Godin :-[)
Is this a MIDI output?
No, 13-pin isn't a MIDI output
per se but it allows you to use any 13-pin device - including guitar synths (Roland GR-series, Yamaha G-10 or Terratec Axon AX-100), guitar to MIDI converters (Roland GI-series or Terratec Axon AX-50) or the Roland VG-series modellers. To drive softsynths (or any other synth), you would also need at least a guitar to MIDI converter.
http://ratcliffe.co.za/articles/midiguitar.shtml
If it can do what I hope it can, for me it will mean that no household in 2009 can be without such an instrument.
All the "synth" playing I do is done with a Ghost equipped guitar and a Roland GI-20 straight into Sonar. Usually at the same time I lay down the rhythm guitar. ?
does this type of connection enable automatic music notation of what's being played the way that a MIDI keyboard does?
With a Guitar to MIDI converter it does. When you output MIDI, any midi stream can be used to notate what you are playing. It's not perfect and some editing is needed to clean up the myriad of small glitches, but it does work.
If it's not MIDI, does it mean it's a Roland hardware specific connection?
No, it's not specifically Roland, but Roland stuff is the most readily available locally (I know Bothners Plumstead have a GI-20 in stock). The Axon is a lot quicker and more accurate if you play with a plectrum (otherwise for a fingerpicker, it's about the same). Axon is now owned by Terratec, but I'm not sure if the local Terratec agents (Turnkey) keep stock.