Serial connection information

Circuit Type		RS-232C			RS-449			C.C.I.T.T Recommendation V.24		Circuit Direction
Common		AB	7	Signal Ground	SG	1	Signal Ground	102	Signal Ground	-
					SC	37	Send Common	102a	DTE Common	To DCE
					RC	20	Receive Common	102b	DCE Common	From DCE
Control					IS	28	Terminal In Service			To DCE
		CE	22	Ring Indicator	IC	15	Incoming Call	125	Calling Indicator	From DCE
		CD	20	Data Terminal Ready	TR	12,30	Terminal Ready	108/2	Data Terminal Ready	To DCE
		CC	6	Data Set Ready	DM	11,29	Data Mode	107	Data Set Ready	From DCE
Data	Primary channel	BA	2	Transmitted Data	SD	4,22	Send Data	103	Transmitted Data	To DCE
		BB	3	Received Data	RD	5,24	Receive Data	104	Received Data	From DCE
Timing		DA	24	Transmitter Signal Element Timing (DTE Source)	TT	17,35	Terminal Timing	113	Transmitter Signal Element Timing (DTE Source)	To DCE
		DB	15	Transmitter Signal Element Timing (DCE Source)	ST	5,23	Send Timing	114	Transmitter Signal Element Timing (DCE Source)	From DCE
		DD	17	Receiver Signal Element Timing	RT	8,26	Receive Timing	115	Receiver Signal Element Timing (DCE Source)	From DCE
Control		CA	4	Request To Send	RS	7,25	Request To Send	105	Request To Send	To DCE
		CB	5	Clear To Send	CS	9,27	Clear To Send	108	Ready For Sending	From DCE
		CF	8	Received Line Signal Detector	RR	13,31	Receiver Ready	109	Data Channel Received Line Signal Detector	From DCE
		CG	21	Signal Quality Detector	SQ	33	Signal Quality	110	Data Signal Quality Detector	From DCE
					NS	34	New Signal			To DCE
					SF	16	Select Frequency	126	Select Transmit Frequency	To DCE
		CH	23	Data Signal Rate Selector (DTE Source)	SR	16	Signaling Rate Selector	111	Data Signal Rate Selector (DTE Source)	To DCE
		CI	23	Data Signal Rate (DCE Source)	SI	2	Signaling Rate Indicator	112	Data Signal Rate (DCE Source)	From DCE
Data	Secondary channel	SBA	14	Secondary Transmitted Data	SSD	3*	Secondary Send Data	118	Transmitted Backward Channel Data	To DCE
		SBB	16	Secondary Received Data	SRD	4*	Secondary Receive Data	119	Receved Backward Channel Data	From DCE
Control		SCA	19	Secondary Request To Send	SRS	7*	Secondary Request To Send	120	Transmit Backward Channel Line Signal	To DCE
		SCB	13	Secondary Clear To Send	SCS	8*	Secondary Clear To Send	121	Backward Channel Ready	From DCE
		SCF	12	Secondary Received Line Signal Detector	SRR	2*	Secondary Receiver Ready	122	Backward Channel Received Line Signal Detector	From DCE
Control					LL	10	Local Loopback	141	Local Loopback	To DCE
					RL	14	Remote Loopback	140	Remote Loopback	To DCE
					TM	18	Test Mode	142	Test Mode	From DCE
Control					SSD	32	Select Standby	116	Select Standby	To DCE
					SB	36	Standby Indicator	117	Standby Indicator	From DCE