EIA-530 Cable Bus




EIA/TIA-530 Description

EIA/TIA-530; High Speed 25-Position Interface for Data Terminal Equipment and Data Circuit-Terminating Equipment, Including Alternative 26-Position Connector

EIA530 Defines a cabling interface between a DTE and DCE device, with pin outs. A replacement for EIA-449 that uses a DB-25 (EIA-232-D) connector instead of a 37-pin connector, while keeping the most important electrical signals intact. A 26 pin connector may also be used. EIA-530 is to be used in conjunction with either EIA-422-A and EIA-423, which defines the electrical drivers and receivers. Nominal maximum signaling rate is 2.1Mbps for both synchronous and nonsynchronous serial binary data. The maximum cable distance is 60 meters.

Two types are circuits are used over EIA-530: Category 1, which have the balanced electrical characteristics of EIA-422-A, and Category 2, which have the unbalanced electrical characteristics of EIA-423. Both types of circuits [depending on the signal] go in both directions. Signal ground is passed between the two devices, but the cable shield is connected to ground on the DTE but not connected on the DCE side.





Category I Category II
Transmitted Data DCE Ready
Received Data DTE Ready
Transmit Signal Timing, DTE Source Ring Indicator
Transmit Signal Timing, DCE Source Local Loopback
Receive Signal Timing, DCE Source Remote Loopback
Request to Send Test Mode
Clear to Send -
Received Line Single Detector -
Ready for Receiver -

EIA-530 Signal Catagory I/II Interface circuits
EIA530 Interface circuits


EIA-530 25 Pin Connector Pin Out
Pin # Circuit Category Connect Direction Description
1
Shield
-
-
From DTE Cable Shield, no connect on DCE
2
BA
I
A - A'
To DCE Tx, Transmit Data
3
BB
I
A - A'
From DCE Rx, Receive Data
4
CA/CJ
I
A - A'
To DCE Request to Send / Ready For Receiving
5
CB
I
A - A'
From DCE Clear to Send
6
CC
II
A - A'
From DCE DCE Ready
7
AB
-
C - C'
- Ground
8
CF
I
A - A'
From DCE Received Line Signal Detector
9
DD
I
B - B'
From DCE Receive Signal Timing
10
CF
I
B - B'
From DCE Received Line Signal Detector
11
DA
I
B - B'
To DCE Transmit Signal Timing
12
DB
I
B - B'
From DCE Transmit Signal Timing
13
CB
I
B - B'
From DCE CTS, Clear to Send
14
BA
I
B - B'
To DCE TXD, Transmit Data
15
DB
I
A - A'
From DCE Transmit Signal Timing
16
BB
I
B - B'
From DCE RXD, Receive Data
17
DD
I
A - A'
From DCE Receive Signal Timing
18
LL
II
A - A'
To DCE Local Loopback
19
CA/CJ
I
B - B'
To DCE Request to Send / Ready For Receiving
20
CD
II
A - A'
To DCE DTE Ready
21
RL
II
A - A'
To DCE Remote Local
22
CE
II
A - A'
From DCE Ring Indicator
23
AC
-
C - C'
- Ground
24
DA
I
A - A'
To DCE Transmit Signal Timing
25
TM
II
A - A'
From DCE Test Mode

The pin out for a 25 pin D type connector is shown above. A 26 pin connector may also be used, in which case pin 26 is a no connect [no signal passed].





Normally EIA422 and 423 systems may not be connected together. EIA-449 cabling of 422 sends and receives data as differential pairs and control signal as single-ended, but for 423 cabling it sends and receives single-ended data and control signals. Receiving the single ended signal in 423 is accomplished by grounding the 'B' side of the differential receiver at the connector.

So if the system does not follow the EIA-449 (cabling) specification than one (B) side of the differential receiver of the 423 side will be grounded at the connector forcing the differential driver on the 422 side to drive ground. The EIA422 side also uses a termination resistor between the ends of its differential receiver, providing a serious 120 ohm short to ground for the 423 driver.

If the systems were to be connected together (with out regard for 499) than the system would revert to EIA423 (single-ended) distance and data rate ~ Only because the driver on the 423 side is single ended, while the receiver on the 422 side would receive the single-ended 423 signal and ground on its differential pair. How ever because 423 and 422 use the same receiver chip; going from 422 to 423 provides a differential path.



EIA/TIA-423 Unbalanced (Single-Ended) interface; specifies a single, unidirectional driver with multiple receivers (up to 10). "..Specifies the electrical characteristics of the unbalanced voltage digital interface circuit, normally implemented in integrated circuit technology, that may be employed when specified for the interchange of serial binary signals between Data Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE) or in any point-to-point interconnection of serial binary signals between digital equipment." 'Telecommunications Industry Association'.
EIA-423 is used in EIA-449 and EIA530, both of which define the cabling and pin-out to form a complete interface.

Transmission Line Drivers and Receivers for TIA/EIA Standards RS-422 and RS-423 {National Semiconductor}
TIA/EIA-422-B Overview {National Semiconductor}


Standard Organizations

ANSI/TIA/EIA-423-B-96 Electrical Characteristics of Unbalanced Voltage Digital Interface Circuits

Telecommunications Industry Association; TIA [www.tiaonline.org]

Note the Electronic Industries Alliance {EIA} ceased operations on Feb 22 2011.
Which would make the standard TIA-423.


Interface ICs

For a listing of Interface or driver IC manufacturers refer to one of the following electrical pages [located on this site]:
RS-232 Bus description, the RS-422 / RS485 Cable Bus, or the RS-423 Cable Bus


EIA-530 is a cable bus. The specification only defines the physical interconnect, the electrical interface is defined in other documents. In this case the EIA-422, EIA-423, EIA485, and EIA-232 standards define the electrical interface [IC switching characteristics].






PC motherboard
Home

Distributor rolodex Electronic Components Electronic Equipment EDA CDROM Software Engineering Standards, BOB card Cabled Computer Bus Electronic Engineering Design Table Conversion DB9-to-DB25.
DistributorsComponents Equipment Software Standards Buses Design Reference

Modified 2/26/12
Copyright © 1998 - 2012 All rights reserved Leroy Davis