PURPOSE: To provide a re-programmable MODEM system which can change firmware having stored operating codes through remote control or improve the grade of the firmware without requiring parts removal nor replacement, the time of engineers, nor any special tool. CONSTITUTION: An updated operating code or parameter can be reprogrammed to a modem system without replacing the hardware of a modem. The modem system incorporates a memory chip which is re-programmable in a circuit in which the operating code or parameter is stored. Two control programs control the re-programming of the updated operating code. One of the control programs is designed for manufacture and tests and the other control program enables the reprogramming of the updated operating code or parameter from a remote place. COPYRIGHT: (C)1995,JPO