The COMX-35 was a home computer that was one of the very few systems to use the RCA 1802 microprocessor, the same microprocessor that is also used in some space probes. The COMX-35 had a keyboard with an integrated joystick in place of cursor keys. It was relatively inexpensive and came with a large collection of software. COMX-35 was manufactured in Hong Kong by COMX World Operations Ltd and was released in the Netherlands, the United Kingdom, Sweden, New Zealand, Australia, Finland, Norway, Italy, Singapore, Turkey and the People's Republic of China. Hardware Technical specifications CPU: RCA CDP1802 at or (NTSC) Random-access memory: ( max) ROM: with BASIC interpreter VIS: (Video Interface System) RCA CDP1869/CDP1870 Text modes: 40 columns x 24 lines. Alternative , and Character set: 128 Programmable characters, the default character set displayed only uppercase characters Character size: 6x9 (PAL) or 6x8 (NTSC) pixels, alternative up to 6x16 Graphics modes: None, but the character-set was re programmable to simulate a High Resolution display Colours: A total of 8 foreground colours are available (with a limited choice of 4 per character and 1 per line of that character) and 8 background colours (defined for the whole screen). Sound: RCA CDP1869 2 channels: one for tone generation with a span of 8 octaves, and 1 for special effect/white noise. Volume programmable in 16 steps. Memory map Memory The COMX-35 has of RAM. It consists of of User RAM of which roughly is available for BASIC code, with the rest reserved for use by the BASIC System ROM. The remaining of RAM is used by the Video Interface System. Video interface system The COMX-35 uses the RCA CDP1869 and CDP1870 Video Interface System (VIS), consisting of the CDP1869 address and sound generator and the CDP1870 colour video generator. The COMX-35 automatically detects the Refresh rate. The VIS runs on in PAL and in NTSC. This frequency is halved and used to clock the CPU. The VIS is also responsible for the timing of the interrupts and non display period. Video memory can only be accessed during the non display period, which allows for execution of 2160 machine cycles in PAL and 1574 cycles in NTSC. To maximize access to the Video memory, the program can be paused until the non display period by checking EF1 in a loop. The Video memory is divided into RAM page memory and RAM character memory.