MD9612FP USER’S GUIDE
0049-1237-XXX
Page 17
REV.
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SW3-7
−
2-/4-Wire Operation
SW3-7
ON = 2-Wire, Half-Duplex Mode
OFF = 4-Wire, Full-Duplex Mode
SW3-7 configures the modem for 4-wire full-duplex or 2-wire half-duplex
operation.
SW3-8
−
Carrier Control
SW3-8
ON = Constant
OFF = Switched
SW3-8 selects either constant or switched carrier. Constant carrier allows DTEs,
such as asynchronous dumb terminals or RTUs, to operate with modems,
without the input RTS signal. When constant carrier mode is enabled (SW3-8 set
to ON), the modem forces the transmit carrier active and the RTS-CTS delay is
minimum (<0.5 ms.).
You can use constant carrier in 4-wire, point-to-point or multi-point applications
(from master to slave modems).
In switched-carrier mode (SW3-8 set to OFF), the RTS/CTS delay is active.
SW3-9
−
RX Termination
SW3-9
ON = Enable Rx Termination
OFF = Disable Rx Termination
SW3-9 selects whether RX termination is enabled for a modem. If you set this
switch ON, the receiver is terminated with 600
Ω
. If you set this switch OFF, the
receiver is not terminated.
SW3-10
−
Grounding Option
SW3-10
ON = Signal Ground and Earth Ground are Connected
OFF = Signal Ground and Earth Ground are Separated
