Teleprinter group terminal system - has test circuit for classification of line signal distortion

摘要

The system has station connector modules (LAM) which each cooperate with a group of stations (T1-n) having equal data rate characteristic, and there are as many such modules as are connected groups of stations with different bit step rates. Each connector module (LAM) is equipped with a test text storage unit (M) wherein test words with predetermined percentage distortion are memorised at addresses from which they may be non-destructively read out at a subscriber station for assessment of its receiving capability. The teleprinter transmitting system can also send out test words which are received by the respective microprocessor allotted to it (MP1-n) and assessed by it. Assessment of signal distortion is carried out by measuring the bit impulse duration and by associating with various durations definite distortion indications. While such test procedures are carried out the flow of incoming or outgoing data at the station-owned microprocessor is impeded.