Unitech HT630. Display resolution: 128 x 64 pixels, Display number of colours: Monochrome. Internal memory: 0.5 MB, Maximum internal memory: 4.5 MB, Internal memory type: RAM. Processor clock speed: 800 MHz. Interface: RS-232. Storage temperature range (T-T): 0 - 50 °C, Operating relative humidity range: 5 - 95 %, Operating temperature range (T-T): -20 - 70 °C