Interfaces used in telecommunication and data communications

Index

• General information
• RS-232
• RS-422 and RS-485
• Other RS standards
• V.35
• Current loop
• Low Voltage Differential Signaling (LVDS)
• Telecommunication systems backplanes
• Other interfaces
• Device connectivity standards

General information

• AN-216: Summary of Electrical Characteristics of Some Well Known Digital Interface Standards - mentions RS-232, RS-422, RS-423, RS-485, EIA/TIA-485, EIA/TIA-562, EIA/TIA-694, EIA/TIA-612, EIA/TIA-644 (LVDS) and more, pdf document
• Data communications introduction by Westermo - a reference covering the basics of data communications from handshaking through the problems of interference to designing networks and selecting communications media
• Data line isolation theory - when it comes time to protect data lines from electrical transients, surge suppression i often the first thing that leaps to mind but sometimes data line isolation is more effective solution
• Dataline surge protection: stop fried boards and garbled data - surges and spikes on datalines can fry your communications boards and garble data, this article describes the operation, installation and selection of what is probably the most common method of data line protection
• Field Buses - interfaces used in industrial automation
• General introduction to serial protocols - National Semiconductors have a several very useful application notes which cover a lot of the basics of balanced serial communications
• Getting from here to there: Serial communication systems - introduction to applications of RS-232, RS-422, RS-485, current loop, fiber optics and wireless
• Going to Ground - information on general instrumentation cables, EMI, EMC, interferences, shielding, balanced line, grounding, includes case study on Lighting & Stage Control
• Hardware data of Apple Macintosh serial modem and printer ports
• Interfaces for industry - short introduction to V.11, RS-422, RS-485, RS-232, TTY, current loop and balanced current loop
• Line drivers and receivers push signals through cable's reality - cable driving is an old art, but new applications such as ADSL/HDSL, cable modems, LANs, and high-resolution video require drivers and receivers that provide increased power, bandwidth, fidelity, and tolerance of line uncertainties
• Multiprotocol transceivers perform feats of champions - Somehow those gigabits of data must get from here to there, and before the job is done, they must be in a format compatible with gear built yesterday or more than a decade ago. No problem.
• RS-232, RS-422 and V.35 interfaces - short description of interfaces and good picture of RS-232 connector
• The problem of interference - up to 70% of all interference during data transmission is due to defective installation or interference from sources near to the equipment, such as neighbouring machinery or cables
• Tips for using Port Powered Converters
• V.35 Tech Info - a high-speed serial interface designed to support both higher data rates and connectivity between DTEs (data-terminal equipment) or DCEs (data-communication equipment) over digital lines

RS-232

The serial interface found on every PC and external modem.

• Apple Macintosh and Newton serial connection
• Do you need information about RS-232C? - enough of the details of the RS-232 standard to allow the construction and/or debuggging of interfaces between any two RS-232 compatible devices
• EIA RS-232C CABLE - many cable wiring examples
• Handshaking - Handshaking is a way for data communication equipment to control the flow of data between connected equipment, it becomes necessary when there is a part of the system that is slower than the rest
• Interfacing a Mac Serial Port to RS-232 Lab Equipment
• New IC Caps Two Decades of UART Development - Maxim has introduced a tiny universal asynchronous receiver/transmitter (UART) MAX3100
• RS232 Connections, and wiring up serial devices - includes wiring for loopback and monitoring
• RS-232C/422/485 line isolation solves more than fault problems
• RS-232 Diagnosis Tech Bulletin
• RS-232C/422/485 line isolation solves more than fault problems - galvanic, or electrical, isolation is a well-established technique for noise reduction and works best in computer and industrial systems in which noise can seriously affect data transfer, isolation removes ground-loop currents and their associated noise voltages from data line
• RS-232 And Modem Connectivity
• RS-232: Connectors and Cabling - DB-25 pinput. DB-9 pinout, information on RJ-45 wiring and RS-232 port setting in UNIX systems
• RS232 Data Interface - a tutorial
• RS232 Serial Troubleshooting
• Serial Communications - information on Mac Serial Port, PC serial port, keyboard port and USB
• What Is RS-232 Communication? - introduction to RS-232 communications

RS-422 and RS-485

Serial interface standards for communicating data at relatively high speed over twisted pair wiring.

• AN-214: Transmission Line Drivers and Receivers for EIA Standards RS-422 and RS-423 - pdf document
• AN-409: Transceivers and Repeaters Meeting the EIA RS-485 Interface Standard - pdf document
• AN-759: Comparing EIA-485 and EIA-422-A Line Drivers and Receivers in Multipoint Applications - pdf document
• AN-979: The Practical Limits of RS - pdf document
• AN-1057: Ten ways to Bulletproof RS-485 Interfaces - pdf document
• Basics of the RS-485 standard
• Cable election for RS-422 and RS-485 systems - selecting the cable is not difficult, but case hould be taken because intermittent problems caused by marginal cable can be very difficult to troubleshoot
• Designing RS-485 Circuits
• Introduction to RS 422 & RS 485
• Quick reference for RS485, RS422, RS232 AND RS423
• Pre-emphasis improves RS-485 communications - intersymbol interference places the main limitation on the maximum allowable distance for RS-485 communications, but pre-emphasis is extremely effective in reducing this interference
• Quick Reference for RS485, RS422, RS232 and RS423
• RS-232C/422/485 line isolation solves more than fault problems
• RS-232C/422/485 line isolation solves more than fault problems - galvanic, or electrical, isolation is a well-established technique for noise reduction and works best in computer and industrial systems in which noise can seriously affect data transfer, isolation removes ground-loop currents and their associated noise voltages from data lines
• RS-422/485 Application Note - contains lots of information
• What is RS485 ? - short description of RS485 interface details
• Ten ways to bulletproof RS-485 interfaces - dispite its widespread use, RS-485 is not as well understood as it should be
• Yhteyskäytäntö RS-422 ja RS-485 - information in Finnish

Other RS standards

• AN-216: Summary of Electrical Characteristics of Some Well Known Digital Interface Standards - mentions RS-232, RS-422, RS-423, RS-485, EIA/TIA-485, EIA/TIA-562, EIA/TIA-694, EIA/TIA-612, EIA/TIA-644 (LVDS) and more, pdf document
• ECL Logic Application Notes
• RS449 Interface
• RS530 Interface

V.35

V.35 interface has been around for quite some time and was originally designed for a 48K bps modem but it has been shown to cope speeds up to 2 Mbit/s and even faster. This interface is most often used with equipment which connect data circuits to syncronous telecommunication network and with some fixed line modems.

• RS-232, RS-422 and V.35 interfaces - short description of interfaces and good picture of RS-232 connector
• V.35 Interface - description of the interface

Current loop

• Circuit translates TTY current loop to RS-232C - provides signal translation between a passive current-loop (TTY) interface and a duplex RS-232C ports
• Current Loop Application Note

Low Voltage Differential Signaling (LVDS)

Low Voltage Differential Signaling (LVDS) is an electrical interface that can quickly handle a large amount of data over long cable lengths. There are currently several industry standards that define LVDS including ANSI/TIA/EIA-644 (EIA-644) and IEEE 1596.3.

• Low-Voltage Differential Signaling (LVDS) Tutorial
• Low-voltage differential signaling yields megatransfers per second with milliwatts of power
• LVDS: power-miser angel, interconnect demon - high data rates and limited signal swing conspire to make the design and characterization of LVDS interconnect systems a tricky proposition
• LVDS Signaling Standard - an overview
• LVDS Signaling Standard Introduction - Low Voltage Differential Signaling (LVDS)
• LVDS Owners Manual & Design Guide
• Signaling system provides speed, noise immunity - LVDS can accelerate performance and reduce power consumption
• Tutorial On LVDS Channel Link - compares LVDS to RS-422 and PECL

Telecommunication systems backplanes

• Breaking The 2.5-Gbit/s Barriers - as Gigabit Ethernet and OC-48/STM-16 nodes start permeating the communications industry, the bandwidth requirements on the line and across the backplane are increasing exponentially, 40-Gbit/s backplane bandwidths are commonplace today and traditional backplane bus structures are on the verge of extinction, the new buzzword is serial
• Design Considerations for Gigabit Backplane Systems Tutorial - This tutorial explores high-speed backplane-interconnect system tradeoffs related to the effects on increases in bandwidth on the signal path from driver to receiver through printed circuit boards (PCBs)
• Designing 2.1V Futurebus+ termination system requires system-engineering approach - designing a termination system for a Futurebus+ power system can be a formidable task
• Differential signaling
• Exploit the potential of high-performance CMOS by selecting best interface - high-speed-bus and point-to-point interfaces between CMOS ASICs are no longer limited to conventional CMOS-level signals
• FAST backplane connectors disguise digital transmission lines - today's telecommunications and high-end computing designs demand backplane edge connectors that maintain signal integrity and provide high signal density for data rates up to 2.5 Gbps
• GTLP Signal Level Background Information - Gunning Transceiver Logic (GTL), approved as a JEDEC Standard JEDS8-3 in 1993, was originally created as a reduced swing I/O driver technology to support high-speed buses and backplanes
• High-speed-connector systems - in high-speed systems, you can't afford to look at connectors as just blobs of plastic and pins
• High-speed serial links benefit from advanced cabling - achieving low bit-error rates on short- and medium-length gigabit/sec links requires examining cable configurations and choosing the right coding and driver/receiver circuitry
• Improve Backplane Performance With Source-Synchronous Designs - source-synchronous interface is an ideal upgrade for passive backplanes and on-card buses
• Serial backplanes supplant parallel buses in fast systems - point-to-point serial links borrowed from industry-standard storage interfaces provide an apt substitute for traditional parallel bus
• System I/O Architects Envision a Packet-Switched Future - As legacy shared bus architectures struggle to cope with endlessly escalating bandwidth requirements, designers set their sights on serial interconnects capable of gigabit speeds

Other interfaces

• 1394 Vs. USB 2.0: What's What?
• ECL Application Notes
• High Speed Interconnect - the technologies and functions used in high-performance data acquisition systems for high-energy physics experiments
• POS-PHY Level 3: Enabling High-Speed Networking Applications - there is call for inter-chip interface to handle sheer variety of services such as ATM, packet over SONET/SDH (POS), Frame Relay, and Gigabit Ethernet
• The Bulky-Data Interface: A Necessity for High-Bandwidth, Time-Critical Data - consumer electronics market converges with the PC market in the digital world, many applications will involve transmitting and receiving high-bandwidth time-critical data like MPEG-2 video, IEEE 1394 is one suitable interface for this
• The High-Speed Alternative of LVDS - compares LVDS to technologies like RS-4222/485, IEEE-644, 3.3V PECL, LVD-SCSI and IEEE 1394

Device connectivity standards

• Jini Community - a place to meet, talk, exchange source code, and advance the goals of Jini connection technology
• Universal Plug and Play Forum - industry initiative designed to enable easy and robust connectivity among stand-alone devices and PCs from many different vendors
• What is Jini Connection Technology? - Jini connection technology provides simple mechanisms which enable device to plug together to form an impromptu community

Related pages

• Data communication circuits
• Telecommunications page
• Telecommunications wiring page