Just as many people don't know that Harrisburg is the capitol of Pennsylvania (no, it's not Philadelphia), many also don't know about the plethora of connector companies located there.

AMP lays claim to being the world's leading interconnect company. In fact, many connector companies can trace their origins back to AMP. Most companies in this central Pennsylvania setting employ engineers who have spent time working for the connector giant or its competitors.

Other major players in the area include Berg Electronics, Phoenix Contact, Stewart Connector Systems, and InterCon Systems. A tour through their plants leaves me with a newfound appreciation for interconnect devices.

Like enclosures, connectors used to be an afterthought. But with signal speeds getting increasingly faster, designers need to make certain that the connector they choose doesn't end up being a bottleneck and forcing a redesign.

Due to this speed increase--and the fact that designers want their products to connect with other companies' products--connector companies play a vital role in setting standards. Today, engineers might settle on a connector or connection standard as a first step in design. They even take advantage of connector companies' SPICE models to completely simulate high-speed circuits.

AMP: Moving beyond hard-wired connections

Founded in 1941, Harrisburg-based AMP Inc. is the granddaddy of all connector companies. You can't drive far in this neck of the woods without passing one of its many buildings.

AMP won't soon abandon its bread-and-butter connectors, but it plans to move beyond its core competencies and play a role in setting standards. For example, one new product--the PHASIR Port--does the work of a connector--but without any wires.

Leveraging a standard from the InfraRed Data Association (IrDA), AMP developed a serial infrared adapter that enables wireless file and data exchanges. The PHASIR port connects to any 9- or 25-position serial connector. It enables communication between two computers or a computer and a peripheral, such as a printer.

One popular use for the adapter is transferring files between portable and desktop computers. As increasing numbers of portable computers come equipped with internal infrared transceivers, many users are retrofitting their desktops with the PHASIR port, rather than dealing with cables or multiple floppy or hard disks.

You use the PHASIR port by pointing it at the second platform's IR transceiver. The baud rate is from 9,600 to 115,200 bps, the transmission range one or two meters. Soon, you'll see PHASIRs with Universal Serial Bus (USB) interfaces. From the start, AMP helped a computer industry consortium that included Intel, which designed the bus's chip set, and Compaq to implement the standard. AMP's part involved the mechanical aspect of the specification, and the firm was first with a USB connector.

These surprisingly small 4-position connectors consolidate serial, parallel, keyboard, mouse, and game ports. "The idea," says William B. Deedy, Jr, director of the computer systems marketing group, "was to make computers easier to use and broaden the base of home users." It's almost impossible to plug this connector in wrong.

AMP has been involved with standards committees for the past five years. In addition to USB, AMP continues to play a role in the Serial Storage Architecture, Fibre Channel, and emerging Very High Density Cabled Interconnect standards.

"Before, connectors were an afterthought for electrical and mechanical engineers. Now, they almost have to think of interconnection first for the sake of compatibility," says Deedy, who expects AMP to continue its standard-setting role.

AMP also gets involved in assemblies--mostly using its own connector products. An example: A docking bar, or port replicator, for portable PCs, which eliminates the hassle of plugging in a monitor, external keyboard, mouse, and printer every time you get back to your desk. Instead, you attach your laptop to the docking bar via one connector. The bar already connects to everything else.

The bar differs from a docking station in that it doesn't include drive bays, speakers, or other electronic equipment--just the essential connectors. It is also much less expensive--typically 80% less than the price of a docking station.

In 1996, you'll see all these products merge into a docking bar with USB connectors and an infrared docking transceiver. "Those plans are definitely on the drawing board," says Market Manager David A. Hernjak, "as we continue to move up the food chain."

Son of AMP, reborn

In 1950, after putting in time at AMP, mechanical engineer Quentin Berg started his own company--with AMP's blessing and financial backing. Also based in Harrisburg, Berg Electronics flourished and provided a second source to AMP.

Twenty one years after Berg sold his company to DuPont in 1972, management firm Mills & Partners, backed by a Dallas investment firm, took over. The new owners restored the Berg name and built the business by acquiring related technology companies. They have also increased capital spending and the R&D budget in the last two years.

Today, Berg Electronics is listed as the world's third biggest connector company. Its 1995 sales of sockets, cable assemblies, and connectors should exceed $650 million.

Technology drives the company, which has an impressive ISO 9001-certified test lab. In 1984, Berg quietly invented the PCMCIA card for a Japanese printer manufacturer who wanted a simple way to load different fonts without programming. Another Berg invention: a patented palladium nickel plating as a low-cost alternative to industry-standard gold.

With Berg continuously turning out such inventions, it's not surprising that three patent attorneys have offices next to the company's engineering department. Designers can have their ideas checked right away for previous patents. Berg was awarded 47 patents in 1994.

"As bus widths and speed increase, connectors can be a system bottleneck," notes Tom Lyons, vice president of engineering. "Today, they're designing computers where connectors are a big deal."

Like AMP, Berg is involved in setting standards. For example, it led the way for the Small PCI (SPCI) standard. The standard describes a 0.8-mm-pitch connector that lets PCMCIA-format cards plug directly into a computer's PCI bus. The connector could also be used in set-top boxes.

Also like AMP, Berg has under development wireless interconnection technologies--helping to build a stepping stone to the company's future.

Where high density means high profits

The move to smaller and denser electronic packages makes high-density interconnections a necessity. As a result, InterCon Systems, a 100-person company in Middletown, PA, that designs and manufactures high-density board-to-board and cable-to-board interconnect systems, looks forward to a bright future. The company prides itself on being innovative and listening and responding to customers.

These qualities have paid off. This year, InterCon Systems' revenue grew more than 25%. Next year, they expect to grow another 25 to 30%.

InterCon's location makes it pretty easy to fill key spots with quality people. "The advantage of a smaller company like ours," says Sales Manager Warren Persak, "is there's not a lot of politics or red tape to deal with."

One new high-density product is shielded to prevent EMI (electromagnetic interference) problems. The 0.050-inch-centerline connector system employs metal plating on Mylar(R) to shield the connector and a metal foil to shield the ribbon cable. The system replaces sub-D SCSI connectors and keeps the same profile as the company's unshielded version. Configurations range from 2x5 to 2x50. It is designed for systems whose signals have subnanosecond risetimes, such as board-to-board data transmission.

"In portable electronic products, such as cell phones and pagers, size is even more important," notes Development Engineer John Walden. To interconnect boards in these applications, designers use only the tiny connectors and forego the cable.

InterCon's new 1-mm-centerline, 2x5 connectors are 20% smaller than 0.050-inch-centerline products. Measuring only 0.067 inch high, Walden believes the connector could be the highest-density, lowest-profile device on the market. He considers this the limit of pin-and-socket technology.

"The next step down will require a new technology, one that won't require molding plastics at 0.01 inch around pins," says Walden. Blade systems fit this scenario. Here, the pins aren't physically isolated. Instead, air provides insulation between contacts.

Bus system drives connector designs

Phoenix Contact Inc. has called Middletown home since its start in 1981. The company is the world leader in its field: manufacturing DIN-rail and pc-board high-density terminal blocks, interface and relay systems, signal-conditioning modules, I/O modules, transient protection devices, power supplies, and distributed I/O systems.

Phoenix products can be found in control and instrumentation systems throughout the industrial process industries. AMP and Phoenix consider themselves competitors only in attracting engineering and other talent.

The company first made its name in terminal-block technology. These devices let you connect wires or wires and boards without using solder or connectors that require crimping. Instead, you insert a wire into the block and screw down the contact to make the connection. You can choose between 1-piece and 2-piece pluggable versions, most of which mount on DIN rails.

Today, the company is miniaturizing its terminal blocks and adding custom circuitry. The goal: easing the connection from an electronic controller having high-density connectors to electrical devices having larger wires. The smallest pitch Phoenix offers is 0.100 inch; the industry standard is 0.200 inch. "To go any smaller," predicts Alan D. Ringhoffer, terminal-block product marketing manager, "we'll have to abandon the screws."

"We make custom products incorporating some of the customer's circuitry," says Product Marketing Manager Joe Pickell. "We help design the circuit board and build in testability and maintainability, which are important in industrial control enclosures." Standard terminal blocks are also available--2,000 catalog pages worth.

Like the other interconnect companies, Phoenix Contact gets involved in standards, particularly the INTERBUS-S version of the fieldbus. INTERBUS-S replaces bulky parallel wire cables from controllers to I/O devices with a single twisted-pair cable. It concentrates multiple proprietary communication networks into a single network. The protocol lets controllers control and monitor with sensors, actuators, and I/O devices at the factory-floor level.

More than 475 manufacturers support this open-standard sensor/actuator bus. Siemens and Oki Semiconductor make INTERBUS-S chips, and General Motors is one of the bus's biggest users.

"The idea is to consolidate wiring and circuitry in one intelligent device that can be networked," says Marketing Manager John F. Rupp. INTERBUS-S is the fastest distributed bus on the global market, he claims.

Phoenix takes advantage of its packaging expertise to put these modules in plastic or aluminum hermetically sealed packages. This protects the electronics from harsh industrial environments and eliminates the need for enclosures. The modules mount on DIN rails. It marks another step in the path to wireless connections.

The house that jacks built

About 45 minutes outside of Harrisburg--right down the road from an AMP building--sits Stewart Connector Systems in Glen Rock, PA. Since being spun off from Stewart Stamping in 1987, it's one of the new kids on the block, but still ranks as one of the ten largest connector companies in the U.S.

Part of Insilico Technologies, Stewart specializes in designing high-speed modular and specialized connector systems for networking and telecommunications equipment, computers, medical instrumentation, and automotive communications systems. One recent innovation: the Harmonica fully shielded, multiport jack system that eliminates EMI while improving high-speed transmission. Stewart engineers also developed surface-mount jacks.

"These connectors are the face of the networking industry," says Andrew MacDonald, managing director of Stewart's German office. "They're what the customer sees."

Stewart engineers continue adding more and more technology to these jack systems and positioning them closer together. Next on the list: integrating magnetics into the jack to offer further cost and space savings and filter out line noise.

One of the newest additions to the product family is a RJ-45 connector system that satisfies EIA/TIA Category 5 performance specifications for high-speed (100-MHz) data transmission over local-area networks. It also can route interactive video and voice. Fore Systems, Pittsburgh, PA, uses the system for its 155-Mbps ATM (asynchronous transfer mode) products, says Engineering Manager Russell Jacobs.

More recently, and in conjunction with Apple Computer and IBM, Stewart developed the P1394 serial bus connector for high-speed computer peripherals. (Texas Instruments designed the bus chip set.) The connector system can transmit data to and from color printers, scanners, monitors, and high-speed disk drives.

Unlike the USB connector, the P1394 also handles the high baud rates of video, making it suitable for digital television, VCR, and cable-TV box applications. Expect to see products sporting this connector in the first half of next year.

After completing a 23,000 square foot addition to its facility in May 1994, Stewart will complete another 35,000 square foot expansion this year. It needs the space: The company has had an average annual revenue growth of 25% in the last five years. "With increasing global sales, there's no end in sight," says Roland Kolu, Insilico Technologies' marketing director.

AMP Technical Marketing Manager Geoff Zech advises Electronics Editor Julie Anne Schofield how to update desktop files from a notebook PC using PHASIR wireless technology (right).

Berg's Small PCI (SPCI) header and receptacle let users plug PCMCIA-format cards directly into a computer's high-speed PCI bus.

This 0.050-inch-centerline connector system from InterCon Systems is shielded to prevent electromagnetic interference. Metal plating on Mylar shields the connector, and a metal foil shields the ribbon cable. The system replaces sub-D SCSI connectors and keeps the same profile as the company's unshielded version.

With INTERBUS-S, intelligent field devices can be networked alongside sensors and actuators. Phoenix Contact manufactures host controller boards, bus terminal modules, I/O modules, and other modules for this open fieldbus.

With a 6-mm height and 0.100-inch pitch, the MPT 0.5 pc-board terminal blocks are the smallest screw-clamp units available, according to developer Phoenix Contact.

RJ-45-style modular connector system from Stewart Connector Systems meets EIA/TIA Category 5 specifications for 100-Mbps data transmission over unshielded twisted-pair cable. The CAT 5 "harmonica" jacks come in shielded versions with up to eight ports, and unshielded versions with up to 13 ports.

RJ-45-style modular connector system from Stewart Connector Systems meets EIA/TIA Category 5 specifications for 100-Mbps data transmission over unshielded twisted-pair cable. The CAT 5 "harmonica" jacks come in shielded versions with up to eight ports, and unshielded versions with up to 13 ports.