EIA530 Interface circuits
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 | - |
| Pin # | Circuit | Category | Connect | Direction | Description |
| Shield | From DTE | Cable Shield, no connect on DCE | |||
| BA | To DCE | Tx, Transmit Data | |||
| BB | From DCE | Rx, Receive Data | |||
| CA/CJ | To DCE | Request to Send / Ready For Receiving | |||
| CB | From DCE | Clear to Send | |||
| CC | From DCE | DCE Ready | |||
| AB | - | Ground | |||
| CF | From DCE | Received Line Signal Detector | |||
| DD | From DCE | Receive Signal Timing | |||
| CF | From DCE | Received Line Signal Detector | |||
| DA | To DCE | Transmit Signal Timing | |||
| DB | From DCE | Transmit Signal Timing | |||
| CB | From DCE | CTS, Clear to Send | |||
| BA |
|
To DCE | TXD, Transmit Data | ||
| DB | From DCE | Transmit Signal Timing | |||
| BB | From DCE | RXD, Receive Data | |||
| DD | From DCE | Receive Signal Timing | |||
| LL | To DCE | Local Loopback | |||
| CA/CJ | To DCE | Request to Send / Ready For Receiving | |||
| CD | To DCE | DTE Ready | |||
| RL | To DCE | Remote Local | |||
| CE | From DCE | Ring Indicator | |||
| AC | - | Ground | |||
| DA | To DCE | Transmit Signal Timing | |||
| TM | 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}
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.
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].
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