Micro-Aide LDM-1 Manual de usuario descargar pdf (Pagina 20)

LDM User Manual

• If two modems are located at an end point in the network only one modem

should be terminated.

• Never terminate a modem located at a drop point.

• There should never be more than two terminations per network channel.

NABLE XMT CHANNEL BUSY DETECTOR (AX3)

The LDM-1 has a built-in carrier detector for its transmit channel. When

enabled, the LDM-1 will not assert its CTS signal until it verifies that a carrier

is no longer present at the transmit channel. This feature prevents two

modems from attempting to transmit simultaneously. To enable the busy

detector, set the AX3 jumper. The factory default setting is Off.

RS-232 P

ROTECTIVE GROUND (AX5)

Installing the jumper at AX5 will connect the signal ground of the LDM-1 to

the protective ground of the DTE device. Generally, the LDM-1 and DTE

can be left isolated from one another by leaving the jumper set to Off. The

LDM-1 is provided 24Vac power by a fully isolated transformer. The factory

default setting is Off.

RTS

TO CTS DELAY (SW2)

The LDM-1 will respond to the DTE’s RTS signal by asserting its CTS signal.

The delay from RTS to CTS is controlled by the SW2 setting. The delay can

be used to ensure that the transmit channel is available. SW2 allows the user to

select any of four settings. Only one switch must be closed. Refer to Table 1

on page 12. Silkscreening on the LDM-1 PCB lists the correspondence

between switch position and delay. The factory default setting is 8msec.

QUALIZATION (SW3)

SW3 is a dual position switch that is accessed from the front panel of the

modem. Refer to Figure 1 on page 6. SW3 allows the user to set the Equaliza-

tion level required to compensate for the transmission characteristics of the

cable being used. To provide the broadest performance range possible, four

CAUTION: Failure to provide the correct termination and Equalization set-

tings can result in significant communication errors.

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Micro-Aide LDM-1 Manual de usuario Pagina 20