Editing VT220 (section)

==Hardware==
[[File:DEC VT240 terminal.jpg|thumb|DEC VT240]]
The VT220 improved on the earlier VT100 series of terminals with a redesigned keyboard, much smaller physical packaging, and a faster microprocessor, the [[Intel 8051]] [[microcontroller]]. The VT220 was available with [[cathode-ray tube|CRT]]s that used white, green, or amber [[phosphor]]s.

The VT100s, like the [[VT50]]s before them, had been packaged in relatively large cases that provided room for expansion systems. The VT200s abandoned this concept, and wrapped the much smaller 1980s-era electronics tightly around the CRT. The result was a truncated pyramidal case with the apex at the back, only slightly larger than the CRT. This made it much easier to fit the terminal on a desk.

Normally the monitor sat facing upward at about a 15 degree angle. Because it was lower than head height, the result was an especially ergonomic terminal. On the rear bottom of the case was a carrying handle that could also be used to angle the monitor more forward. An extendable post could do so to even greater angles, allowing the monitor to face directly forward.

The [[LK201]] keyboard supplied with the VT220 was one of the first full-length, low-profile keyboards available; it was developed at DEC's [[Roxbury, Boston|Roxbury]], [[Massachusetts]] facility. It was much smaller and lighter than the VT100s version, and connected to the terminal using a lighter and more flexible coiled cable and a [[telephone jack]] connector.

The VT200s were the last DEC terminals to provide a [[Digital current loop interface|20mA current loop serial interface]] (using a 8-pin [[Molex connector|Molex]]-style connector), an older standard originally developed for the [[telegraph]] system but became popular on computers due to the early use of [[Teletype Model 33]]'s as ''ad hoc'' terminals. A standard 25-pin D-connector was also provided for RS-232. Only one of the two ports could be in use at a given time. Later DEC terminals would replace both of these with their proprietary [[Modified Modular Jack]] (MMJ) connectors.

Another version of the terminal, the VT240, used DEC's own [[DEC T-11]], a single-chip microcontroller version of the [[PDP-11]] [[minicomputer]].
The VT241 is the color version of the VT240, consisting of the same V240 base unit with VR-241 color monitor. A VT240 can be upgraded to a VT241 by replacing the monitor and the cable.