Rohde & Schwarz FSEA20 - RS-232-C Interface; Interface Characteristics; Signal Lines

Contents - Maintenance and Instrument Interfaces FSE
1065.6016.12 8.6 E-15
RS-232-C Interface
The standard FSE is equipped with two serial interfaces (RS-232-C). The RS-232-C interfaces are two
independent, remote-control channels, both of which may be active at the same time. The programming
and interrogation commands affect the same instrument hardware. The interfaces can be set up
manually in the SETUP-GENERAL SETUP menu in the COM PORT1/2 table.
Each of the active RS-232-C interfaces is assigned to one of the 9-pin connectors located on the rear
panel. Interface 1 is assigned to the connector COM1 and Interface 2 is assigned to the connector
COM2.
Interface Characteristics
•
Serial data transmission in asynchronous mode
•
Bidirectional data transfer via two separate lines
•
Transmission rate selectable from 110 to 19200 baud
•
Logic ’0’ signal from+3 V to +15 V
•
Logic ’1’ signal from -15 V to -3 V
•
An external instrument (controller) can be connected.
•
Software handshake (XON, XOFF)
•
Hardware handshake
1
5
6789
234
DCD
RxD
TxD
DTR
SG
DSR
RTS
CTS
RI
Fig. 8-2 Pin assignment of the RS-232-C interface
Signal Lines
1. Data lines
The data transmission is bit-serial in ASCII code starting with the LSB. Two lines, RxD and TxD are
necessary as the minimum requirement for transmission; however, no hardware handshake is
possible. For handshaking, only the XON/XOFF software handshake protocol can be used .
RxD (Receive Data)
Input, LOW = logic ’1’, HIGH = logic ’0’.
Data line, local terminal receives data from remote station.
TxD (Transmit Data)
Output, LOW = logic ’1’, HIGH = logic ’0’.
Data line, local terminal transmits data to remote station.
2. Control lines
DCD (Data Carrier Detect),
Not used in FSE.
DTR (Data Terminal Ready),
Output, active LOW,
Indicates that the local terminal is ready to receive data.