Распиновка, расположение выводов и внешний вид последовательного интерфейса:
EIA-449 (RS-449)
Common names: EIA-449, RS-449, ISO 4902
Primary channel
(at the DTE)
(at the DCE)
CORRECT?
37 PIN D-SUB MALE at the DTE (Computer).
37 PIN D-SUB FEMALE at the DCE (Modem).
PinNameV.24DirDescriptionType
1
101
Shield
Ground
2
SI
112
Signal Rate Indicator
Control
3
n/a
n/a
unused
4
SD-
103
Send Data (A)
Data
5
ST-
114
Send Timing (A)
Timing
6
RD-
104
Receive Data (A)
Data
7
RS-
105
Request To Send (A)
Control
8
RT-
115
Receive Timing (A)
Timing
9
CS-
106
Clear To Send (A)
Control
10
LL
141
Local Loopback
Control
11
DM-
107
Data Mode (A)
Control
12
TR-
108.2
Terminal Ready (A)
Control
13
RR-
109
Receiver Ready (A)
Control
14
RL
140
Remote Loopback
Control
15
IC
125
Incoming Call
Control
16
SF/SR+
126
Signal Freq./Sig. Rate Select.
Control
17
TT-
113
Terminal Timing (A)
Timing
18
TM-
142
Test Mode (A)
Control
19
SG
102
Signal Ground
Ground
20
RC
102b
Receive Common
Ground
21
n/a
n/a
unused
22
SD+
103
Send Data (B)
Data
23
ST+
114
Send Timing (B)
Timing
24
RD+
104
Receive Data (B)
Data
25
RS+
105
Request To Send (B)
Control
26
RT+
115
Receive Timing (B)
Timing
27
CS+
106
Clear To Send (B)
Control
28
IS
n/a
Terminal In Service
Control
29
DM+
107
Data Mode (B)
Control
30
TR+
108.2
Terminal Ready (B)
Control
31
RR+
109
Receiver Ready (B)
Control
32
SS
116
Select Standby
Control
33
SQ
110
Signal Quality
Control
34
NS
n/a
New Signal
Control
35
TT+
113
Terminal Timing (B)
Timing
36
SB
117
Standby Indicator
Control
37
SC
102a
Send Common
Ground
Note: Direction is DTE (Computer) relative DCE (Modem).
NameDescriptionFunction
AA
Shield Ground
Also known as protective ground. This is the chassis ground connection between DTE and DCE.
AB
Signal Ground
The reference ground between a DTE and a DCE. Has the value 0 Vdc.
BA
Transmitted Data
Data send by the DTE.
BB
Received Data
Data received by the DTE.
CA
Request To Send
Originated by the DTE to initiate transmission by the DCE.
CB
Clear To Send
Send by the DCE as a reply on the RTS after a delay in ms, which gives the DCEs enough time to energize their circuits and synchronize on basic modulation patterns.
CC
DCE Ready
Known as DSR. Originated by the DCE indicating that it is basically operating (power on, and in functional mode).
CD
DTE Ready
Known as DTR. Originated by the DTE to instruct the DCE to setup a connection. Actually it means that the DTE is up and running and ready to communicate.
CE
Ring Indicator
A signal from the DCE to the DTE that there is an incomming call (telephone is ringing). Only used on switched circuit connections.
CF
Received Line Signal Detector
Known as DCD. A signal send from DCE to its DTE to indicate that it has received a basic carrier signal from a (remote) DCE.
CH/CI
Data Signal Rate Select
(DTE/DCE Source>
A control signal that can be used to change the transmission speed.
DA
Transmit Signal Element Timing
(DTE Source)
Timing signals used by the DTE for transmission, where the clock is originated by the DTE and the DCE is the slave.
DB
Transmitter Signal Element Timing
(DCE Source)
Timing signals used by the DTE for transmission.
DD
Receiver Signal Element Timing
(DCE Source)
Timing signals used by the DTE when receiving data.
IS
terminal In Service
Signal that indicates that the DTE is available for operation
NS
New Signal
A control signal from the DTE to the DCE. It instructs the DCE to rapidly get ready to receive a new analog signal. It helps master-station modems rapidly synchronize on a new modem at a tributary station in multipoint circuits
RC
Receive Common
A signal return for receiver circuit reference
LL
Local Loopback / Quality Detector
A control signal from the DTE to the DCE that causes the analog transmision output to be connected to the analog receiver input.
RL
Remote Loopback
Signal from the DTE to the DCE. The local DCE then signals the remote DCE to loopback the analog signal and thus causing a line loopback.
SB
Standby Indicator
Signal from the DCE to indicate if it is uses the normal communication or standby channel
SC
Send Common
A return signal for transmitter circuit reference
SF
Select Frequency
A signal from the DTE to tell the DCE which of the two analog carrier frequencies should be used.
SS
Select Standby
A signal from DTE to DCE, to switch between normal communication or standby channel.
TM
Test Mode
A signal from the DCE to the DTE that it is in test-mode and can’t send any data.
Reserved for Testing
Contributor:
Joakim Цgren
Source:
RS449 Page made-it.com/CKP/rs449.html at Connectivity Knowledge Platform (Made IT)
Copyright © The Hardware Book Team 1996-2004.
May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2002-01-13