B&B Electronics QSPXP-100 - Manual - Manual (Page 31)

B&B Electronics ExpressCard Serial Adapter User’s Manual Using configuration utilities
Rev 1.00 (July 2007) Page 27
Receiver Control (RS-422/485 adapters only)
In RS-422/485 half-duplex operating modes, the serial port’s receivers
can be set to be active all the time or to be active only when the port
is not transmitting. The desired choice is selected from the dropdown
box.
Always (default)
Select this option to force the receivers to be active all the time. This
selection will cause the receiver to hear the echo of whatever the
serial port transmits.
Only when not transmitting
This selection is useful for scenarios where the serial port should not
hear the echo of its own transmissions. The receivers will be disabled
whenever the serial port transmits data.
Connector Set-up : AuxOut/AuxIn (RS-422/485 adapters only)
This setting determines which signals are routed to the AuxIn and
AuxOut pins of the serial port connectors. Regardless of which setting
is chosen, each UART's DTR output is internally looped back to its
own DSR, DCD, and RI inputs.
Loopback (default)
Select this choice when only transmit and receive data signaling is
required.

Each UART's RTS output is internally looped back to its CTS
input.

Each port's AuxIn signal pair is looped back to its AuxOut
signal pair at the connector.
Modem Control
Select this choice when hardware flow control is required.
 Each UART's RTS output and CTS input are routed to the
AuxOut and AuxIn signal pairs, respectively.
Clocks
Select this choice when it is necessary to connect together two ports
at different baud rates. In order to properly function, both ports must
support and have the feature enabled.

Each UART's RTS output and CTS input are looped back
together.

The UART’s transmit clock (TClk) is fed out to the AuxOut
line.

The UART’s receive clock (RClk) is fed in from the AuxIn line.