We’ll have to wait a bit yet for the first ARM RISC-based line but London-based electronic organizer market leader Psion Plc yesterday moved to defend its leadership with two new models for its range of palmtop computers. The 3c, replacing the 3a, has either 1Mb or 2Mb of internal memory and two expansion slots for extra memory, at around $550 and $650. A new built in RS232 serial port for direct connection to a range of devices, including modems and mobile phones will support access to the Internet. The new Siena, targeted at those more familiar with conventional paper-based or simple electronic databank systems, condenses the key organizer functionality of the 3a into a 6.4oz pocket-sized case with either 512Kb or 1Mb of memory. Its powered by a pair of AAA batteries that will last for about 40 hours of continuous usage and will retail at approximately $300 and $320. Both machines use the same 80C86-compatible NEC Corp V30H processor running at 7.68MHz and embedded in semi-custom ASIC. Both include infra-red capabilities to enable information to be transferred wirelessly from a Psion to a printer, personal computer or another Psion. But UK managing director Peter Norman said it would be some time before the company produced a combined phone and organizer similar to that recently launched by Nokia Oy. He thinks Nokia’s 9000 model has resulted in too big a compromise to be commercially acceptable: it’s neither a good mobile phone or organizer and acknowledged that Psion’s labs were working on something better.