RS-232 CONTROL
Connectingthe RS-232 Port
48 SuperView3000 User Manual May9, 2002
A
Almostall ASCII terminals, and most computer serial ports, are configured as
Data TerminalEquipment. To connect these to the SuperView,you need a
“straightthrough” cable with pins 1 through 8 connected. “Straight through”
implies that pin 2 is connected to pin 2, etc. The cable will have a 9-pin male
plug on SuperView’send, and t he appropriate gender of a 9-pin connector on
theo ther end. Most ASCII terminals and host computers have a 9-pin female
connectorfor their RS-232 port. This cable may be up to 50 feet long for regular
cable,or s ubstantially longer for low capacitance cable. Depending on the
signalsused, one or more of the conductors internal to the cable may not be
needed.
THE NULL
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MODEM
Youmay need to connect the SuperView’s serial port to a host computer
configuredas Data Communications Equipment. This is done using a null
modem.Th e neteffect of a null modem is to reverse the Transmitted Data and
ReceivedData connections. Also, the Request to Send and Clear to Send
connectionsare reversed. This may b e done by using a special “null modem”
cable,or by inserting a small “null modem” box or cable in series with a regular
“straightthrough” cable.