Black Box ME444AE-530-R3, ME444AE-R3, ME445C-X.21, ME445C-35, ME444A-R3 User-configurable options

256-KBPS LINE DRIVER (V.35, RS-530, OR X.21)

Table 3-1 (continued). User-configurable options.

Element	Function	Possible	Standard
		Settings	Factory
			Setting
J4	Select the delay in milliseconds that	0
RTS-CTS	occurs during RTS-to-CTS transitions.	9	9 ms
DLY jumper	Do not select 0 for multipoint applications.	70
J5	Turn V.54 delay ON or OFF. When you turn	ON
V54 DLY	it ON, V.54 delay prevents multiple loopback	OFF	OFF
jumper	of tail-end circuits.
J6	Enable or disable the DIG, ANA, and REM	ON	ON (enabled)
SW. EN.	loopback-control buttons on the unit’s front	OFF
jumper	panel.
J7	Enable or disable electronic control of	EN	EN (enabled)
RLB DTE**	remote digital loopback testing through the	DIS
jumper	DTE interface.
J8	Enable or disable electronic control of	EN	EN (enabled)
ALB DTE**	local analog loopback testing through the	DIS
jumper	DTE interface.
J9	Select the level (in dBm) of receive	-6
RCV LVL	input from the line.	0	0 dBm
jumper
J10	Select the receive-line impedance. In	150 [Ω]	150 ohms
RCV IMP	multipoint applications, it is advisable to	HIGH
jumper	set the master modem and the last modem
	in the line to 150 Ω, and all others to HIGH.
J11	Enable or disable the remote power	ON	ON
RPF.	failure feature.	OFF
jumper
J12	Select the level (in dBm) of transmit	-6
XMT LVL	output to the line.	0	0 dBm
jumper
J13	Select the transmit-line impedance in	150 [Ω]	150 ohms
XMT IMP	ohms. In multipoint applications, it is a	LOW
jumper	good idea to set the master modem to
	“LOW.”
J14	Set to CON to connect signal ground to	DIS
CHASS	chassis ground. Set to DIS to keep the	CON	CON (connected)
jumper	two grounds isolated from each other.
**NOTES:	If the DTE does not provide the test pins for analog and remote loopback, the ALB DTE
	and RLB DTE jumpers must be always set to DIS.

18