Black Box LRU4240 manual Unit Problems 3

		Dual Trunk E1 Router
	Table 11-1 Unit Problems (3 of 4)
Symptom	Probable Cause	Solution
No response from any unit on the	• Bad cable.	• Make sure that Pin 8, CTS, is not
communication network.	• Wrong baud rate.	connected at the ASCII terminal
		end of the COMM Port cable.
	• Hung terminal. Restart terminal
		• Standard Black Box COMM Port
	session.
		cables do not have this connection
		at the ASCII terminal end. Some
		ASCII terminals will activate the
		CTS line, and thus interfere with
		the LRU4240 collision avoidance.
		• Get a null modem adapter to cross
		pins 2 and 3 (transmit and receive)
		on the terminal.
		• The COMM Port cable is connected
		to an inactive or faulty port on the
		terminal, or the terminal is faulty.
		• Replace the COMM Port cable if it
		is faulty.
		• Make sure the COMM Port
		parameters match the terminal’s
		parameters.
No response from some units on	• Mismatch baud rate.	• Make sure the LRU4240 is
the network.	• Break in cable.	powered up.
		• Make sure the unit ID is correct.
		• Swap the connector positions with
		a unit that has no problem
		communicating with the terminal,
		to find out if a portion of the
		COMM Port cable is faulty.
		• Make sure the COMM Port
		parameters match the terminal’s
		parameters.
Invalid data is received from one	• Baud rate configuration.	• Make sure the COMM Port
or all units on the network.	• EMI.	parameters (on the problem units)
		match the terminal’s parameters.
	• Two units with the same ID.
		• Verify that none of the units are
		missing an ID and that no two units
		have the same unit ID.

Dual Trunk E1 Router User’s Guide TECHNICAL: 0118 96 56 000 89