Black Box MD1970A, Руководство пользователя

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Installing the Modem
Jumper S1
−
Carrier Detect Control
Settings: -33 dBm ( default )
-43 dBm
Jumper S1 configures the dynamic range of the modem receiver. The selections are either –33 dBm or –43 dBm. If
the incoming signal is above –24 dBm, use the default –33 dBm setting. If the modem is operated on the network,
use the –43 dBm setting.
Jumper S2
−
Transmit Level
Settings: 0 dBm ( default )
-2 dBm
-4 dBm
-6 dBm
-8 dBm
-10 dBm
-12 dBm
-14 dBm
Jumper S2 adjusts the modem’s transmit level. There are eight transmit level settings you can choose. By default,
the modem uses a transmit level of 0 dBm.
Jumper S3
−
2-wire/4-wire Mode
Settings:
2-wire
4-wire (
default )
Jumper S3 configures the modem for 2-wire or 4-wire operation.
™ When configured for 4-wire full-duplex operation, jumper S5 can be strapped to maintain constant carrier from
the master modem to all slave modems at all times after the initial training. This enables the master modem to
transmit data to the slave modems, with no RTS-to-CTS delay. This is the preferred operating mode when
minimum turnaround is desired.
™ When configured for 2-wire half-duplex operation, the modem encounters an RTS-to-CTS delay when
transmitting to slave modems, increasing the turnaround time. Set jumper
S5 to controlled carrier for 2-wire
half-duplex operation.
Jumper S4
−
Call Turnaround Squelch
Settings: Enabled
Disabled (
default )
Jumper S4 configures the modem’s Call Turnaround Squelch setting. For 2-wire, half-duplex communications, set
this strap to the Enabled position. In this position, the receiver is inhibited for a period of time after the local
transmitter is turned OFF. This guards against echoes caused by the transmission just completed. The time is
determined by the turnaround squelch time option (jumper
S11 ).
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