Tag Line Monitor
Original Publication Date: 1981-Oct-01
Included in the Prior Art Database: 2005-Feb-12
Invalid "handshaking" at a standard RS-232 interface is detected by monitoring the tag lines between the terminal and its modem. The five lines (request to send (RTS), clear to send (CTS), data terminal ready (DTR), data set ready (DSR) and transmit data (TXD)) are logically connected to latch in error status when the proper signal sequence fails to occur.