56
IM 767361-01E
Overview of the RS-232 Interface
Table of RS-232 Standard Signals and Their JIS and CCITT Abbreviations
Table of Signals
Pin Number
Abbreviation
Name
(25-pin connector) RS-232
CCITT
JIS
1*
AA (GND)
101
FG
Protective ground
7*
AB (GND)
102
SG
Signal ground
2*
BA (TXD)
103
SD
Transmitted data
3*
BB(RXD)
104
RD
Received data
4*
CA(RTS)
105
RS
Request to send
5*
CB(CTS)
106
CS
Clear to send
6
CC(CSR)
107
DR
Data set ready
20
CD(DTR)
108/2
ER
Data terminal ready
22
CE(RI)
125
CI
Ring indicator
8
CF(DCD)
109
CD
Data channel received carrier detect
21
CG(-)
110
SRS
Data signal quality detect
23
CH/CI(-)
111
SRS
Data signal rate select
24/15
DA/DB(TXC) 113/114
ST1/ST2
Transmitter signal element timing
17
DD(RXC)
115
RT
Receiver signal element timing
14
SBA(-)
118
BSD
Secondary transmitted data
16
SBB(-)
119
BRD
Secondary received data
19
SCA(-)
120
BRS
Secondary request to send
13
SCB(-)
121
BCS
Secondary clear to send
12
SCF(-)
122
BCD
Secondary received carrier detect
* Pins used by the MT200 or MT200 series or this instrument RS-232 interface.
Handshaking
To use an RS-232 interface for transferring data between the instrument and
a PC, it is necessary to use certain mutually determined procedures to ensure
the proper transfer of data. The execution of these procedures is called
handshaking. There are many different handshaking methods corresponding
to the different possible combinations of instruments and PCs, so it’s necessary
choose the same handshaking method for this device and the PC.
This instrument allows you to choose any handshaking mode from the following
eight modes.
Data sending control
(Control method when
sending data to a PC)
Data receiving control
(control method when receiving
data from a PC)
Software
Handshake
Software
Handshake
0(OFF-OFF)
1(XON-XON)
2(XON-RTS)
3(CTS-RTS)
Mode Selection
No.
(Handshaking
method)
Sending
stops when
X-off
received, and
resumed
when X-on
is received.
Sending
stops when
CB(CTS) is
False, and
resumed
when CB is
True.
No
handshake
No
handshake
X-off is sent
when received
data buffer
becomes 3/4
full, and X-on
is sent when
the received
data buffer
is only 1/4 full.
CA(RTS) is set
to Falso when
received data
buffer is only
3/4 full, and is
set to True
when received
data buffer
is only 1/4 full.
Hardware
Handshake
Hardware
Handshake
Table of Handshaking Methods ( = Function Available)
