|
RS-232 Signals (DB-25) "EIA-232-D"
|
|
Pin
|
Signal
Name |
Abbreviation
|
RS-232 Ref.
|
Signal
Function |
|
1
|
Shield
/ Protective Ground / Frame/ Chassis |
SHD
|
AA
|
Ground |
|
2
|
Transmitted
Data |
TD ("TXD")
|
BA
|
Data,
to DCE |
|
3
|
Received
Data |
RD ("RXD")
|
BB
|
Data,
from DCE |
|
4
|
Request
to Send |
RTS
|
CA
|
Control,
to DCE |
|
5
|
Clear
to Send |
CTS
|
CB
|
Control,
from DCE |
|
6
|
DCE
("Data Set Ready") |
DCR ("DSR")
|
CC
|
Control,
from DCE |
|
7
|
Signal
Ground (Common Return) |
SGND
|
AB
|
Ground |
|
8
|
Received
Line Signal Detector "Carrier Detect" |
RLSD ("CD","DCD")
|
CF
|
Control,
from DCE |
|
9
|
+12VDC
(reserved for testing) |
|
|
|
|
10
|
|
|
|
|
|
11
|
|
|
|
|
|
12
|
Secondary
Carrier Detect |
SCD
|
SCF
|
Control,
from DCE |
|
13
|
Secondary
Clear to Send |
SCTS
|
SCB
|
Control,
from DCE |
|
14
|
Secondary
Transmit Data |
STD
|
SBA
|
Data,
To DCE |
|
15
|
Transmitter
Signal Element Timing |
TSETC
|
DB
|
Timing,
From DCE |
|
16
|
Secondary
Receive Data |
SRD
|
SBB
|
Data.
From DCE |
|
17
|
Receiver
Signal Element Timing (Receive Clock) |
RSETC
|
DD
|
Timing,
from DCE |
|
18
|
Local
Loopback |
LL
|
LL
|
Control,
to DCE |
|
19
|
Secondary
Request to Send |
SRTS
|
SCA
|
Control,
to DCE |
|
20
|
DTE
Ready (Data Terminal Ready) |
DTR
|
CD
|
Control,
to DCE |
|
21
|
Remote
Loopback |
RLSD ("CD","DCD")
|
RL
|
Control,
to DCE |
|
21
|
Signal
Quality Detector |
SQD
|
CG
|
Control,
from DCE |
|
22
|
Ring
Indicator |
RI
|
CE
|
Control,
from DCE |
|
23
|
Data
Signal Rate Selector (DTE Source) |
DSRST
|
CH
|
Control,
to DCE |
|
23
|
Data
Signal Rate Selector (DCE Source) |
DSRSC
|
CI
|
Control,
from DCE |
|
24
|
Transmitter
Signal Element Timing (DTE Source) |
TSETT
|
CA
|
Timing,
To DCE |
|
25
|
Test
Mode |
TM
|
TM
|
Control,
from DCE |
|
|
|
|
|
|
RS-232 Signals (DB-25) "EIA-530"
|
|
Pin
|
Signal
Name |
Abbreviation
|
RS-232 Ref.
|
Signal
Function |
|
1
|
Shield
/ Protective Ground / Frame/ Chassis |
SHD
|
AA
|
Ground |
|
2
|
Transmitted
Data A |
TD A
|
BA
|
Data,
to DCE |
|
3
|
Received
Data A |
RD A
|
BB
|
Data,
from DCE |
|
4
|
Request
to Send A |
RTS A
|
CA
|
Control,
to DCE |
|
5
|
Clear
to Send A |
CTS A
|
CB
|
Control,
from DCE |
|
6
|
DCE
("Data Set Ready") A |
DCR A
|
CC
|
Control,
from DCE |
|
7
|
Signal
Ground (Common Return) |
SGND
|
AB
|
Ground |
|
8
|
Received
Line Signal Detector "Carrier Detect" A |
RLSD A
|
CF
|
Control,
from DCE |
|
9
|
Receiver
Signal Element Timing (Receive Clock) B |
RSETC B
|
DD
|
Timing,
from DCE |
|
10
|
Received
Line Signal Detector "Carrier Detect" B |
RLSD B
|
CF
|
Control,
from DCE |
|
11
|
Transmitter
Signal Element Timing (DTE Source) B |
TSETT B
|
CA
|
Timing,
To DCE |
|
12
|
Transmitter
Signal Element Timing B |
TSETC B
|
DB
|
Timing,
From DCE |
|
13
|
Clear
to Send B |
CTS B
|
CB
|
Control,
from DCE |
|
14
|
Transmitted
Data B |
TD B
|
BA
|
Data,
to DCE |
|
15
|
Transmitter
Signal Element Timing A |
TSETC A
|
DB
|
Timing,
From DCE |
|
16
|
Received
Data B |
RD B
|
BB
|
Data,
from DCE |
|
17
|
Receiver
Signal Element Timing (Receive Clock) A |
RSETC A
|
DD
|
Timing,
from DCE |
|
18
|
Local
Loopback |
LL
|
LL
|
Control,
to DCE |
|
19
|
Request
to Send B |
RTS B
|
CA
|
Control,
to DCE |
|
20
|
DTE
Ready (Data Terminal Ready) A |
DTR A
|
CD
|
Control,
to DCE |
|
21
|
Remote
Loopback |
RLSD ("CD","DCD")
|
RL
|
Control,
to DCE |
|
21
|
Signal
Quality Detector |
SQD
|
CG
|
Control,
from DCE |
|
22
|
DCE
("Data Set Ready") B |
DCR B
|
CC
|
Control,
from DCE |
|
23
|
Data
Signal Rate Selector (DTE Source) |
DSRST
|
CH
|
Control,
to DCE |
|
23
|
DTE
Ready (Data Terminal Ready) B |
DTR B
|
CD
|
Control,
to DCE |
|
24
|
Transmitter
Signal Element Timing (DTE Source) A |
TSETT A
|
CA
|
Timing,
To DCE |
|
25
|
Test
Mode |
TM
|
TM
|
Control,
from DCE |