Excuse my noob-ness

[reptileink]

What exactly do you need a keyboard for in the arcade cab? For the function keys? Tab? what? I understand the mouse, but is it possible to not use a keyboard?

[Ginsu Victim]

If you're confident that your computer is set up good enough not to need tweaks, then it's fine not to have one in it.  In the beginning stages of your MAME cab, though, you'll definitely want one handy.

I just plug one in when I need it these days, which isn't that often. Also, most the time I just use the onscreen keyboard in Windows when I can get away with it.

[BadMouth]

I have one wireless usb keyboard and mouse set that I use on both my jukebox and driving cab.
It has a small usb dongle the size of a flash drive.  It's simple just to plug it in when it's needed.

My main setup (which isn't a cab) uses an X-arcade which requires a keyboard be plugged into it. 

Whenever I get around to building a custom cp & cab, ther is no way I'm going to bother with a keyboard tray.

[gryhnd]

My upright has a wireless KB/mouse combo in a tray hiding under the CP. This is because my kid and his friends also play other games on it: SIMs, P.O.C., Halo, etc

My cocktail does not have a KB, but I do have an hidden USB port to plug one in when needed.

[Malenko]

For using a keyboard.   I have a TINY USB keyboard under my controls, comes in handy when I need to use windows

[BobA]

I use a tiny wireless KB touchpad controller.

Link to Review

[JustMichael]

What exactly do you need a keyboard for in the arcade cab? For the function keys? Tab? what? I understand the mouse, but is it possible to not use a keyboard?

You might need a mouse and keyboard when updating the roms on your cab or if you are changing the way your cab is set up.  For normal use of the cab, you should not need either.  My cab doesn't have a mouse or keyboard plugged into it (not counting the I-pac).  I do have an old usb hub on the back right side of the cabinet in case I need to plug in a keyboard and mouse.