MODEM ZUR UEBERTRAGUNG MIT EINER GESCHLOSSENEN ELEKTRONISCHEN EINRICHTUNG

摘要

A portable interface unit incorporates a modem for connecting a personal computer through a bidirectional communication link to enclosed process control equipment by passing radiation, preferably infra-red radiation, through a casing enclosing the unit. The computer has a bidirectional digital serial interface specified in accordance with an industry standard, and the modem has a complementary bidirectional digital serial interface, an optical modulator and an optical demodulator, and a power supply. The power supply can be a circuit to derive power from the serial interface of the personal computer, or from a battery. The portable interface unit provides a versatile bidirectional communications link which is particularly suitable for use in hazardous environments and with electronic equipment designed to be environmentally sealed or tamperproof, and permits general purpose computers to be used to program, diagnose, configure or interrogate such equipment.