Editing BTC 8120 (section)

==Description==
BTC 8120 is a split-body ergonomic keyboard: the two sides snap together, and can be pulled apart to allow them to be positioned and angled separately. Each side has two dual-height feet with screw-out posts at the rear and two screw-out feet at the front to provide tenting in a variety of angles, including both front-to-back and sideways negative tilt on each side. The keyboard case is shaped so that the bottom parts serve as built-in wrist rests on each side.

An integrated cable with 25 or 26 conductors connects the matrix wiring and the electromagnetic shielding on each side. This cable terminates internally in each side with two plugs, one 15-way and one 10-way; the 15-way plug is fully populated, while the 10-way plug may only use nine of the positions (this is not clear from the photographs). The grounding conductor is separate.

The layout is non-standard, and is based (depending on target locale) on [[ISO]] and the [[Focus layout]]. Most of the navigation cluster is moved to the top above and to right of the function keys, but arrow keys are brought in closer and duplicated on the left-hand side. The space bar is split, providing [[Erase-Eaze]]: the left side of the space bar functions as backspace. The label cites US patent 5143462, for Erase-Eaze.

Both examples below use [[BTC dome with slider]] switches; the second example is demonstrated to use a PCB. The 8210 specification sheet posted to the BTC website cites the "switch activation mechanism" as "Membrane", which could either be plain rubber dome as in the [[BTC 8110M]], or it could be the membrane version of BTC dome with slider. A limited amount of thin foil appears to offer some kind of electromagnetic shielding.

The manual below gives the tactile force as 60±20 g, while the specification sheet online gives 55±20 g.