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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).
Pin | Name | V.24 | Dir | Description | Type |
---|---|---|---|---|---|
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).
Name | Description | Function |
---|---|---|
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 at Connectivity Knowledge Platform (Made IT) |
Информация предоставлена справочником The Hardware Book Team 1996-2004.
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