Black Box BRTS-100 Passive Bus-Check Terminations, Passive Bus Configuration Check Terminations

BRTS-100 ISDN TEST SET

4.5 Passive Bus—Check Terminations

When you’re using a passive-bus configuration, it’s imperative that the last device on the bus be terminated at 100 ohms. The other devices on the bus must be left unterminated. Termination should be an option on each ISDN terminal. Refer to your terminal’s user manual to determine how to configure the terminal in terminated/unterminated mode.

See Figure 4-7 for an outline of the functions performed in this test.

Passive Bus Configuration
Check Terminations	PB1

Test Set should be in NORMAL mode

GO TO FIRST

DEVICE ON BUS

	NO	YES
	TERMINAL SHOULD	IS TERMINAL
	NOT BE TERMINATED	LAST DEVICE?
	PUT CIRCUIT IN
	CONFIG. 3, POWER
	DOWN TERMINAL
	IMPEDANCE
	GRN	RED
	TEST STATUS?
	RED
UNTERMINATE	DEVICE PROPERLY	TERMINATE
TERMINAL	TERMINATED
		DEVICE
	POWER UP
	TERMINAL, GO TO
	NEXT DEVICE
	ON BUS

TERMINAL SHOULD

BE TERMINATED

PUT CIRCUIT IN

CONFIG. 3, POWER

DOWN TERMINAL

IMPEDANCE

TEST STATUS?

GRN

ALL

DEVICES

PROPERLY

TERMINATED

Figure 4-7. Passive bus flow chart.

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