Black Box ME759C-RJ45 Cable Box User Manual


 
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MULTI-FUNCTION LD CARD
NOTE
We cannot guarantee that the Card will accurately detect small pieces of
flat satin cable in the line if they are farther than 1500 ft. (457.2 m) from
the local modem.
C. If one wire among the four twisted-pair wires is broken, the Error
LED and the green CD LED will both light on at least one of the
modems.
5.2.2 D
ETECTING
S
TREAMING
E
RRORS
When the Multi-Function LD Card is not in test mode (its green Test LED is
dark), the front-panel Error LED can also indicate streaming errors. When
the Card’s antistreaming circuitry is enabled (one or both of switch S3
positions 7 and 8 set to “On”), the RTS signal from the attached DTE is timer-
controlled. The timer begins to count down when the DTE raises RTS. If RTS
remains high for longer than the preset timeout period, the antistream circuit
will force RTS low. The Error LED will light, indicating a streaming condition
(RTS continually on). This feature prevents a malfunctioning terminal from
tying up a computer port in a multidrop or polling environment.
When the DTE drops RTS, the antistreaming timer is automatically reset
and the Error LED goes dark. The timeout period is user-selectable for 12.5
or 50 seconds. See Section 3.1.4.
5.3 Power-Up
There is no power switch on the Multi-Function LD Card: Power is
automatically applied to the Card whenever—and for as long as—its card-
edge connector is plugged into the MicroRack’s mid-plane socket and the
MicroRack’s power supply is turned on.
NOTE
The Multi-Function LD Card is a “hot-swappable” card—it will not be
damaged by plugging it in or removing it while the rack is powered up.