The EIA/TIA-449 is a general purpose
37-Position Interface for Data terminal Equipment and Data
Circuit-Terminating Equipment Employing Serial binary Data
Interchange |
The pinout for the 37-pin connector is listed below.
The pin out for the 9-pin connector is listed on the main EIA-449 Bus page.
Pin | name | V.24 | Description | Type |
---|---|---|---|---|
1 | 101 | Shield | Ground | |
2 | SI | 112 | Signal Rate Indicator | Control |
3 | 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 | 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 |
Data Rate | Cable Length |
2 Mb/sec | 15.24 Meters |
1 Mb/sec | 30.48 Meters |
512 Kb/sec | 60.96 Meters |
256 Kb/sec | 121.92 Meters |
128 Kb/sec | 243.84 Meters |
56 K | 487.68 Meters |
1.2 Kb/sec | 914.40 Meters |
name | Description | Function |
---|---|---|
AA | Shield Ground | Protective ground. Chassis ground connection between DTE and DCE. |
AB | Signal Ground | Ground |
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 | ---- |
CC | DCE Ready | DSR. Originated by the DCE indicating that it is operating |
CD | DTE Ready | DTR. Originated by the DTE to instruct the DCE to setup a connection |
CE | Ring Indicator | Signal from the DCE to the DTE that there is an in-comming call |
CF | Received Line Signal Detector | 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. Instructs the DCE to rapidly get ready to receive a new analog signal |
RC | Receive Common | A signal return for receiver circuit reference |
LL | Local Loopback / Quality Detector | Control signal from the DTE to DCE that causes the analog transmission 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 |
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. |
RS449 is the old term for EIA449. The term RS [Recommended Standard] was replaced in the 70's by the term EIA.
However as of 2011 the EIA group disbanded, which would make this the TIA449 interface.
Back to the main EIA-449 Bus page for a description and pinout of a 9-Pin D connector.
Navigation: Engineering Home > Interface Buses > Cabled Interface Standards > EIA-449 Bus > RS449 variations.
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