Modem Connect Line Interchange Circuits NCL Attribute Name Circuit Description ---------------------------------------------------------------------- carrier detect RR Receiver Ready clear to send CS Clear to Send data set ready DM Data Mode data terminal ready TR Terminal Ready local loopback LL Local Loopback remote loopback RL Remote Loopback request to send RS Request to Send ring indicator IC Incoming Call signalling rate SI Signaling Rate Indicator indicator signalling rate SR Signaling Rate Selector selector test mode TM Test Mode