Specifications

SW3-6 − Reserved (Test Only)
SW3-6 Must be OFF
SW3-6 must be in the OFF position for normal operation.
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
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