The Gemini 1000 and 2000 offer the features and performance of a single/dual level preset counter or a programmable sample time rate indicator in one economically priced package. The reliability of solid-state MOS technology coupled with the flexibility of user programmable functions makes these units ideally suited to handle practically any preset control application. As a counter, the Gemini 1000/2000 offers a choice of six (6) programmable counting modes to cover Bi-directional, Anti-Coincidence, and Quadrature applications. The input circuitry is switch selectable to accept signals from a wide variety of sources. In addition, the unit may be programmed to register counts on both edges of the input signal thus providing frequency doubling capability. The choice of several reset cycle modes along with the compatibility of count and control inputs to other RLC products, provides added versatility for both stand-alone and systems counter needs. As a rate indicator, the Gemini 1000/2000 features crystal-controlled accuracy along with a variety of data sampling times to allow the needed resolution for precision applications. The combination of 5-digit scale factor and decade scale multipliers provide a wide range of scaling correction for direct readout in terms of units being measured. The Gemini 2000 20 mA Current Loop Option provides the capability of two-way communications between the Gemini 2000 and a variety of equipment, such as a printer, remote terminal, or host computer. The Baud rate can be set to 300, 600, 1200 or 2400 baud. The format for transmitted and received data is 1 start bit, 7 data bits, 1 parity bit (odd), and 1 stop bit. When utilizing an external power supply (30 VDC max), up to 16 units can be installed in the loop, each with an individual address. When utilizing the Gemini's 20 mA current source, up to seven units can be installed in a loop. The Count value, Scale Factor, and Preset values can be interrogated. The Scale factor and Presets can be changed by sending the proper command codes and numerical Data. Other functions such as resetting the count, and a combined transmit count and reset can also be performed. Various "Print Options" can be selected to automatically interrogate the Count Value, Preset, or Scale Factor by activating the "Print Request" terminal when a printer is being used, or by sending a "transmit per Print Options" (P) command. All command codes and numerical data are sent in ASCII. The construction of the Gemini 1000/2000 features a zinc die-cast bezel offering maximum durability with a high quality appearance. The sealed front panel meets NEMA 4/IP65 specifications, for wash-down and/or dust when properly installed. Electrical connections are made via pluggable terminal strips at the rear of the unit. Clamp-type pressure plate terminals accept stripped #14 AWG wire without lugs.