The 300-series machines provided similar functionality to the desktop 100-series machines, but packed the functions into a smaller, easily portable, battery-operated package. The advances in integrated circuit technology that were incorporated into the ACL chipset allowed a practical battery-powered calculator to be made. The machines included a battery compartment into which either disposable D-cell batteries, or rechargeable Nickel-Cadmium cells could be installed. An external power-pack provided ability to operate on AC power, as well as serving as a charger if NiCad batteries were installed in the machine. Due to the fragile nature of Nixie tube displays, the display technology used in the 300-series machines changed to the new Burroughs Panaplex II seven-segment planar gas-discharge display. The Panaplex display was more durable, less expensive, and could be made smaller to fit within the confines of a 'handheld' device. The 300-series calculators were marketed both by Compucorp, as well as through Monroe. The machines in the series included the Model 320, 320G, 322, 322G, 324G, and 326G Scientist calculators; the Model 340, 342, and 344 Statistician machines; the Model 360 and 360/65 Bond Trader/Financial calculators; and the Model 354 Surveyor. Some of the programmable 300-series machines provided the ability to connect a specialized cassette recorder to in order to provide off-line storage for programs and data, a real advantage when volatile RAM was used to store programs. Along with cassette tape program and data storage, there were numerous other interfaces for the 300-series calculators. Peripheral options included the Model 300 I/O Writer, the Model 310 Data Coupler Interface, and the Model 395 Teleprinter-Serial I/O Interface.

Our machine has a serial number of 5424691 and was made in the USA. Our machine is in working condition and is complete with the AC power supply.

Manufacturer: Sumlock
Date: 1979

This exhibit has a reference ID of CH30957. Please quote this reference ID in any communication with the Centre for Computing History.

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