User’s Manual UDP6722 Programmable DC Power Supply
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RS-232 is the current widely used serial communication, it also known as the asynchronous
communication. It is used for data communication between computers and computers,
computers and peripherals. RS is the abbreviation of "Recommended Standard", 232 is the
standard number, the standard is officially published by the American Electronics Industry
Association (EIA) in 1969. It requires one bit send by a data line at a time. Usually, RS232 interface
comes in the form of 9 pins (DB9) or 25 pins (DB25). The most commonly used RS-232 signals are
shown in the following table:
Table Common RS-232 Signal
Signal
Abbreviation
Pin of 25-core
connector
Pin of 9-core
connector
Request To Send
RTS
4
7
Clear To Send
CTS
5
8
Data Set Ready
DSR
6
6
Data Carrier Detect
DCD
8
1
Data Terminal
Ready
DTR
20
4
Transmitted Data
TXD
2
3
Received Data
RXD
3
2
Common Ground
GND
7
5
Except the above table, RS232 also has the minimum subset and that is the connecting way used by
the instrument.
Table Minimum Subset of RS-232
Signal
Abbreviation
Pin of 9-core
connector
Transmitted Data
TXD
2
Received Data
RXD
3
Common Ground
GND
5
15.1.2 RS-232 Connecting
The instrument uses DB9 (femal head) interface.
Suggestion: To avoid electric shock, please turn off the power supply when plug the
connector.
Figure 14-1 Interface Definition of DB9 (femal head) Front View
Connecting the instrument to PC via a direct line that has DB9 male head and DB9 femal head.
