Microprocessor controlled message handling system

A dial-up communication system for transmitting and receiving messages over telex, TWX and DDD lines, comprising:

• dial-up means;
• first and second message handling units;
• a communication line coupling said first and second message handling units together;
• and
• a plurality of low-speed communication terminals coupled to each of said message handling units via said dial-up means for communication therewith, each of said message handling units comprising:
• a system bus
• first memory means coupled to said bus for storing system operating programs;
• second memory means coupled to said bus for storing said messages;
• multichannel multiplexing means coupled between said bus and said telex terminals;
• modulator-demodulator means coupled between said multiplexing means and said TWX and DDD terminals;
• and
• microprocessor means for providing on said bus write and read memory command signals and a signal representation of a memory location of means connected to said bus to cause said memory location to respectively store a signal on data lines of said bus and to cause said memory location to provide a signal on said data lines.