One of the problems which appears while debugging of microprocessor systems or hardware-program complexes through interface RS-232C is a development of test software. This test software must be universal for debugging any devices of specified class. And it should be also comprehensible and suitable when are used by the developers of equipment and programmers.The program Terminal RS-232C satisfies this condition. The program can send the sequences data determined by user as well as respond to certain requests. This allows not only testing the separate instrument, but also emulate the behaviour of the separate instrument. The Program works at any PC, which uses MS Windows 95/98/NT4/2000/XP operating systems. The Program perceives specially designed scenario of the protocol of the exchange through interface RS-232C to provide versatility of the testing of any equipment. The User interface in program allows comfortable and accustomed work the developer, loading files with scenario. As well as allows to view information on given exchange through RS-232C such as sent and taken bytes, COM port status lines, errors of the exchange. There is also a possibility of documentation of exchange information in output text file.