Black Box 3600 MODEM manual Telephone Line Connection

Installation

Table 2-1. Pin Signal Descriptions (Continued)

	EIA-	CCITT
Pin	232D	V.24	Signal	Description
20	CD	108.2	Data	This circuit is positive when the
			Termi-	DTE is ready to originate or
			nal	answer a call in dial-up operation.
			Ready	DTR must always be active (high)
				in 2-wire private line operation.
				Cycling DTR causes retraining.*
21	--	140	Remote	A positive level causes a digital
			Digital	loopback test mode at the remote
			Loop-	modem.*
			back
22	CE	125	Ring	In direct dial operation this circuit
			Indicator	is positive in response to an
				incoming ring signal.*
23	CH	111	Data	Supplies a data rate control input
			Rate	to select primary or fallback data
			Select	rate: Negative voltage selects
				primary data rate and positive
				voltage selects fallback data rate.*
24	DA	113	External	A serial data rate clock input from
			Trans-	the data source. Positive clock
			mit	transitions correspond to data
			Clock	transitions.
25	--	142	Test	Indicates the modem is in a test
			Mode	mode.

** Modem options may force these signals on or cause them to be ignored.

*** Refer to Appendix C, Hardware Options.

*† This function can be disabled or its logic sense reversed by hardware straps.

Telephone Line Connection

The modem operates in these line-related modes:

•Dial

•Leased

2-6 Modem 3600