I happen to have a nearly mint condition MessagePad 110. The first thing that one notices is the fine attention to detail, the smooth lines and nice rubberized grip. If you push the button on the bottom of the unit, the screen protector can flip back over the top to clip onto the battery compartment, which takes regular, unmodified AA batteries, unlike the MessagePad 100/OMP (AAAs), the eMate and the 2000 series (custom pack).
On the right, there is a PCMCIA card slot that can hold a modem or linear flash card plus probably a bunch of other minor things. Towards the rear, there is a power adapter port and a round 8-pin RS422 serial port. You can either use a regular Mac printer cable (the included one is black) or an adapter for use with windows. Software for synchronization is available at the UNNA. For that matter, for any Newton software, try the UNNA.
In the very top right, there is a round hole. If you push the 'button,' it will extend the stylus so that it can be pulled out. If it doesn't lock open in this time frame, if you relock the stylus' extension and let it spring open under its own power, it should lock. Alternately, just pull it a little bit further upwards and it should click into place.
On the let, there is a contrast wheel and a power switch. The switch can be difficult to press, but a finger nail makes it nice and easy. On the bottom is the battery compartment and two little silver plates in the bottom right.
What these do is connect to a MessagePad 110 (and probably 120-130) charging station, which basically cradles it perfectly with the lid open with an 'inkwell' for the stylus at the top end. It manages to charge my batteries in about a half an hour. Bear in mind that it takes anywhere from five days to five weeks to discharge these batteries. It's insane. On the bottom of the dock, there are two lights: one to say if the MessagePad is charging or done and the other to say if the second battery that can be inserted underneath the MessagePad is charging or done. These lights remain off if there is no contact. Because the real estate on my power strip is sparse, I use it as a stand and only plug it in when it needs charging.
When you turn it on, you should arrive at Notes (this applies to NOS 1.3), which is for either sketches or, well, notes. Along the bottom of the screen, the Names, Dates, Extras, Undo, Find and Assist buttons along with the navigation controls are all permanently visible. The OS is overly self explanitory and seems to be crash proof, bullet proof, idiot proof, fire proof and water proof. It doesn't crash at all. If it does, open the battery compartment and press the reset button with your stylus. It reboots in five seconds flat. For the sake of time (July 30 at 13:03 PDT!), I'm going to can it here and direct you to my Newton OS page for a guide featuring general points of each. A note with the 110: if you use 1.2V rechargable AAs, it may display an error (-539 million something or other) and deactivate the power switch. This is solved by recharging the batteries. My theory is that the old NiCd batteries were not designed to be drained all the way while the NiMH batteries that I use today can be. I suspect that the low voltage (1.2V vs 1.5V for alkalines) causes problems with the power manager. Strangely, this only happens in NOS 1.3. There is no problem with NOS 1.2, what it shipped with.