‘Transmission seems to be very good;’ the TAT-1 project

@MarkOllig

The project to install the Transatlantic Telephone Cable System No. 1 (TAT-1) was officially announced Dec. 1, 1953.

Earl De La Warr, Britain’s postmaster general, hailed the installation of this transatlantic cable as “the beginning of a new chapter in the history of communications.”

It would be the first submarine telephone cable to cross the Atlantic Ocean, linking the United States and the United Kingdom.

Before TAT-1, transatlantic calls relied on a 12-circuit radiotelephone system that was frequently disrupted by atmospheric conditions; TAT-1 would provide a more stable service and triple the capacity to 36 circuits.

The TAT-1 project was a collaboration between American Telephone and Telegraph Co., the Canadian Overseas Telecommunications Corp., and the UK’s British Post Office, which was also the United Kingdom’s telecommunications carrier.

The $42 million construction cost (about $506 million today) was split: Canada paid 10%, the UK provided 40%, and the US covered 50%.

In 1953, Her Majesty’s Telegraph Ship (HMTS) Monarch, a British 480-foot cable vessel, was recognized as the “world’s largest cable ship.”

The HMTS Monarch played a vital role in the TAT-1 cable project by transporting the large spools of coaxial cables in its four cable tanks.

Each TAT-1 cable consisted of three parts: two armored shallow-water sections and a continuous central section of about 2,244 statute (land) miles that crossed the North Atlantic Ocean from Gallanach Bay, near Oban, Scotland, to Clarenville, Newfoundland.

From Clarenville, a separate coaxial submarine telephone cable crossed the Cabot Strait to Sydney Mines, Nova Scotia; this extension was 271 nautical miles long (nautical is a unit of distance used in sea navigation).

From Sydney Mines, microwave radio relay and landline circuits carried the communications onward to Portland, ME, and then to New York, NY, via the US Public Switched Telephone Network.

The HMTS Monarch laid the cable between Oban, Scotland, and Clarenville, Newfoundland, during the summers of 1955 and 1956.

The TAT-1 deep-sea system had two 1.625-inch coaxial cables spaced about 20 miles apart for bidirectional communication: one for west-to-east and the other for east-to-west traffic.

Each cable had a solid copper core, thick polyethylene insulation, and reinforced steel armor-wire tapes for strength and corrosion protection.

It was laid at an average depth of 2.5 miles in the ocean, withstanding 6,000 pounds of pressure per square inch.

The cables included repeaters (boosters) placed at different intervals to amplify the signal across the Atlantic.

In deep-sea sections, repeaters were spaced 37.5 nautical miles apart, while in shallow waters, they were about 20 nautical miles apart.

Western Electric, a subsidiary of AT&T, produced eight-foot-long repeaters that boosted audio signals using high-gain vacuum tubes to achieve a 65dB audio gain.

The repeaters were contained in watertight casings made of overlapping steel rings and copper tubes, designed to withstand deep-sea pressure.

Each repeater had a lifespan of 20 years and operated on about 4,000 volts of direct current (DC).

Power was supplied from shore stations in Clarenville, Newfoundland, and Labrador, and Oban, Scotland, minimizing electrical losses over the 2,240-mile distance.

DC power was delivered through the central conductor of the coaxial cable, necessitating that the repeaters be wired in series.

Each repeater contained Western Electric 175HQ vacuum tubes, which were assembled in extremely clean conditions comparable to those used in early semiconductor manufacturing to ensure their longevity.

The reliable operation of the TAT-1 repeater system resulted from the high quality of the vacuum tubes and gas tubes designed to bypass faulty component stages in the event of a failure.

TAT-1 offered 36 circuits in total. Of these, 35 were for two-way voice telecommunications – 29 connecting New York and London, and six connecting Montreal and London.

The 36th circuit was used for telegraph services.

TAT-1 was completed in July 1956, with the final cable splices being made in Newfoundland.

A seven-minute, three-way telephone call took place between officials in New York, London, and Ottawa, Canada, Sept. 25, 1956.

“I now declare the cable open for service between the United States and the United Kingdom,” said AT&T chairman Cleo F. Craig in New York.

A recording of this historic call can be heard at .

In its first 24 hours of public service, TAT-1 carried 588 calls between London and the United States and 119 between London and Canada.

A three-minute call between Minneapolis and London was priced at $12 ($141 today) on weekdays and $9 ($106 today) on Sundays (plus tax, of course).

The Minneapolis Morning Tribune reported that media representatives met with Northwestern Bell (now Lumen Technologies) officials at 224 S. Fifth St. in Minneapolis Sept. 26, 1956.

They spoke with Albert J. Semkens, a senior telecommunications superintendent in London, over the new transatlantic cable.

“We are in Lancaster House, in the heart of historic London,” Semkens said.

“Transmission seems to be very good. I can hear every inflection in your voice,” a Northwestern Bell official replied.

In 1960, the TAT-1 cable’s capacity was upgraded to 72 audio circuits.

TAT-1 began carrying the circuit for the Moscow-Washington “hotline” Aug. 30, 1963.

In 1978, TAT-1 was retired, and its telephone traffic transferred to higher-capacity cables that had been installed across the Atlantic, such as TAT-6 and TAT-7.

The Leich Dial System kept the town talking: part two

@Mark Ollig


From 1960 to 1986, the Leich (pronounced “like”) electromechanical all-relay dial system processed phone calls for the subscribers of the Winsted Telephone Co.

The main distribution frame (MDF), a two-sided steel frame approximately 15 feet long and 10 feet high, served as the physical connection point between outside telephone line cable pairs (external network) and the Leich call processing switch.

The back side (or vertical side) of the MDF, where the outside cable pairs terminated, contained rows of terminal blocks attached vertically along the full height of the frame.

A terminal block was a rectangular block of insulating Bakelite (the first synthetic plastic), approximately 10 inches wide and seven inches deep, fitted with rows of metal lugs that provided dedicated, fixed points for soldering telephone jumper wires.

The cable pairs were soldered to the left-hand metal terminal posts (lugs) of a vertical terminal block.

The corresponding right-hand terminal posts were left open, ready to be cross-connected with a jumper wire to the Leich switch when a specific cable pair was assigned to a new subscriber.

All cable pairs were wired through a two-stage protection system to handle two distinct electrical threats.

The primary defense against high-voltage surges was a carbon block protector, also known as a lightning arrester.

It featured a small air gap that would arc during a surge, creating a path to safely divert the dangerous voltage to the office grounding system and protect the Leich switch.

The second stage used a heat coil to guard against “sneak currents,” which are sustained, low-voltage overcurrents too weak to cross the air gap.

Unable to arc across the carbon protector, the current flowed through the coil, melting a solder pellet to release a spring-loaded mechanism that grounded the line and protected the Leich switch.

On the frame’s front side (or horizontal) side, wiring from the various Leich switch circuits was permanently soldered underneath ten horizontal rows of individual terminal blocks spanning the length of MDF.

Dedicated terminal blocks included line finders, hundreds groups, party-line assignments, trunking, and miscellaneous blocks.

We soldered the MDF cross-connections using “jumper wires,” typically 22 AWG or 24 AWG solid copper.

Jumper wires for subscriber lines on the vertical side of the MDF were wired to their assigned terminal block circuits on the horizontal side.

To provision a line, we first used rosin-core solder to connect one end of a jumper wire to the subscriber’s assigned cable pair on the vertical side of the MDF.

This first jumper was run to the horizontal side and connected to the subscriber’s assigned line finder circuit terminal block.

From that same terminal, a second jumper was then run to the connector block associated with the last four digits of the telephone number.

For an assigned number like 485-4111, this second jumper was terminated on the ‘41’ hundreds-group block and soldered to the specific terminal lugs representing ‘11’, completing the physical path to the correct Leich connector circuits.

For multiparty lines, an additional, separate sleeve wire was run from the associated hundreds group to a dedicated terminal block for party-line assignments.

To minimize the risk of short circuits from splattering solder, we placed a heavy canvas apron over the lower terminal blocks.

Today, MDFs use solderless wire wrap terminations.

When a subscriber lifted the handset, it completed a circuit that signaled the Leich switch.

A line finder would then connect the subscriber’s line to the first available link relay, which provided a dial tone.

After the last dialed digits, the call was sent through the Leich switch.

The voice call path activated the movement of thin, gold-dipped metal crosspoint contacts (yes, real gold) to ensure voice-quality consistency.

Leich documentation described them as “bar-type twin contacts of precious metal.”

I recall the sound of the distinctive “buzz” dial tone generated by a vibrating reed interrupter inside a sealed metal container powered by 48 VDC.

We described the dial tone as sounding like “a bee in a can.”

Many of the relay bars featured Sylvania lamps to indicate the status of active switching selector links, which also aided when troubleshooting.

I recall replacing many of those lamps when one burned out.

In 1981, the Winsted Telephone Co. installed dual-tone multifrequency (DTMF) equipment, allowing the Leich switch to decode tones from subscriber touch-tone keypads.

As a separate but related project that same year, the Leich switch’s “bee in a can” dial tone was replaced with a precise, dual-frequency tone (350 Hz and 440 Hz), as specified in the Bell System’s precise tone plan.

In 1986, Winsted Telephone Co. upgraded from its 26-year-old Leich platform with a Northern Telecom DMS-10 digital call-processing switch.

The DMS-10 used pulse code modulation (PCM) and time division multiplexing (TDM), with programming done through a VT-100 terminal.

That same year, we installed a new MDF using 88 Series Terminal Blocks with wire wrap termination – using, you guessed it, a wire wrap tool to securely wrap jumper wires around the metal terminal posts.

I was certified on the DMS-10 and maintained it for many years; I found it to be an excellent voice-switching platform.

Today, Winsted TDS Telecom telephone subscribers use the Metaswitch platform.

The different kinds of systems used through the years.

The Metaswitch is a “softswitch” that employs Voice over Internet Protocol (VoIP) technology.

The voice packets are transmitted with transport layer security (TLS) for signaling and secure real-time transport protocol (SRTP) for voice encryption.

I was certified on the Metaswitch platform and spent eight years working with it prior to my retirement.

Reflecting on my 13 years with the Leich switch, one memory that stands out is giving tours to students from the local Winsted schools.

They were fascinated by the telecommunications equipment, attentively watching and listening to the rhythmic clicking of the relays as they observed the blinking lights of the selector links.

The students paid close attention as we demonstrated how telephone calls were processed, and they especially liked seeing where their phone’s dial tone originated.

Yes, the old Leich Dial System kept the town talking.

The Leich Dial System kept the town talking: part one

@Mark Ollig


The Leich (pronounced “like”) Dial System was a telephone call switching platform manufactured by Leich Electric Co. during the 1950s and 1960s.

At the core of the Leich Dial System were its relay bars, which its 1959 catalog advertised as a “jacked-in design permitting easy installation, reconfiguration, and maintenance by simply removing or inserting the entire bar into a shelf slot.”

Averaging 22.5 inches in height and 2.5 inches in width, each relay bar weighed between 10 and 15 pounds and contained numerous relays and electrical components on its front side.

The backside contained a central terminal connector with two parallel rows of copper contacts.

This design enabled the relay bar to be inserted directly into, or removed from, a series of corresponding jacks on the shelving bay’s backplane, providing a secure, solderless connection.

Relay bars were configured as hundred-group line finders and connectors, relay links, first, second, and fifth selector switches, fire bars, interoffice trunking circuits, and more.

In 1960, the Winsted Telephone Company installed the Leich TPS (Terminal Per Station) electromechanical voice switch.

My father, John Ollig, his brother Jim, and Kenny Norman from the telephone company, along with Bud Miller from General Telephone and Electronics and three technicians from Automatic Electric, completed the installation.

The Leich switch replaced the Winsted Telephone Company’s 1940s-era Wilcox Electric step-by-step system, which used rotary selectors.

The Leich equipment bays, measuring three feet wide and seven feet, five inches high, were located in the secure dial room of the telephone office, which featured brick walls and a 10-foot ceiling.

Arranged in three 25-foot aisles, the overhead bay interconnected shelving cables were neatly bundled, often sewn together with twine, and supported in racks about six inches above the bay cabinets.

These cables were the physical medium that established a coordinated voice-switching platform.

Each bay shelf had transparent Plexiglas covers in aluminum frames to protect and provide a visual display the relay bars.

The Leich switch housed hundreds of relay bars, with more added over the years as new bays and shelves were installed to support the growing number of telephone subscribers.

The switch processed the dialed digits from rotary telephones at a speed of eight to 12 pulses per second and supported telephone line loop resistances up to 1,200 ohms.

In 1960, the Leich switch used a ringing generator supplying 70 to 106 volts of alternating current (AC) at a frequency of 20 cycles per second, now referred to as hertz (Hz).

During ringing, this AC voltage was superimposed through a cut-through relay to the telephone line and into the subscriber’s telephone.

Winsted Telephone Company equipped all their telephones with single-frequency 20 Hz ringers, and subscribers leased their phones directly from the company.

On a private line, the Leich switch sent the 20 Hz AC ringing voltage across the telephone line’s tip and ring wires to activate the telephone’s ringer.

For a two-party line, however, the switch achieved selective ringing by sending this same 20 Hz AC ringing voltage down either the “tip” or “ring” wire side, activating only the telephone specifically wired to respond to that side.

For four-party lines, the Leich system, combined with specific in-telephone wiring and central office configuration, enabled selective ringing.

This ringing configuration was achieved by creating a “polarized” ringer in each telephone, which involved wiring each phone with an inductor to respond to the 20 Hz ringing frequency and a cold-cathode vacuum tube to verify the ringing voltage’s positive or negative polarity.

The Leich switch leveraged the sleeve lead (single wire) party positions at the main distribution frame to send “divided ringing” (selecting either the tip or ring wire) and apply a specific DC polarity.

This combination generated four unique ringing configurations, ensuring only the intended telephone on the shared line would ring.

On eight or 10-party lines, the Leich system used coded ringing, which involved applying the ringing voltage in a unique pattern of short and long bursts assigned to each subscriber.

The Winsted Telephone Company’s central office battery room contained 24 large lead-acid cells housed in thick, rectangular glass containers known in the industry as battery jars.

Each 150-pound cell contained heavy lead plates immersed in sulfuric acid.

The glass jar provided a stable, non-reactive barrier to safely contain the corrosive acid while also allowing for visual inspection of electrolyte levels.

Wired in series, these 24 cells formed a single battery, with each cell contributing 2.1 to 2.2 volts DC to provide a total voltage of 50.4 to 52.8 volts DC.

The central office power plant used a rectifier to convert commercial AC to DC for powering the Leich switch’s call-processing systems and ancillary devices.

It maintained a 50 to 54 volt DC float charge on the 24-cell battery, ensuring the Leich switch operated within its required 44 to 54 volt DC range.

This float charge ensured that the battery remained fully charged, allowing the Leich switch and connected subscriber telephones to continue operating even during a commercial power outage.

Anyone with a Winsted party line might recall this announcement: “You have dialed a subscriber on your own line; please hang up to allow their telephone to ring. Thank you.”

Leich kept the whole town of Winsted talking.

Next week: part two.

The journey to Direct Distance Dialing

@Mark Ollig


The Bell Telephone Company was founded July 9, 1877, in Boston, MA, by Alexander Graham Bell, his father-in-law Gardiner Greene Hubbard, and financial backer Thomas Sanders.

It merged with the New England Telephone and Telegraph Company Feb. 17, 1879, to become the National Bell Telephone Company.

The company would manage the production, leasing, and installation of telephones and exchanges through the use of Bell’s patents.

The National Bell Telephone Company merged with the American Speaking Telephone Company to form the American Bell Telephone Company March 20, 1880, which became the central corporate entity for Bell interests in the US.

AT&T (American Telephone and Telegraph) was incorporated March 3, 1885, as a subsidiary of the American Bell Telephone Company.

In 1899, AT&T acquired the assets of the American Bell Telephone Company, becoming the parent company of the Bell System.

AT&T laid the foundation for a nationwide telephone network that began as an infrastructure of local telephone exchanges wired to open galvanized iron wires, similar to telegraph lines, strung and fastened on glass insulators attached to the wooden crossarms of telephone poles.

This early infrastructure formed a long-distance backbone between towns and cities, including New York City and Boston in 1885 and Chicago in 1892.

By 1920, the US network had more than 13 million telephones and approximately 32 million miles of telephone wire in use, forming a coast-to-coast network for long-distance calls.

Before 1951, making long-distance calls required telephone operators in different cities along the telephone network to manually patch connections through multiple switchboards, a process that could be time-consuming.

During the 1940s, efforts were already underway to reduce the time it took to process a call through the use of automated telephone switching equipment.

My mother and grandmother were switchboard operators in the 1930s and 1940s; my mother worked in Silver Lake, and my father’s mother worked in Winsted.

They told me stories of people calling the switchboard to ask who had died, where the fire was, why the church bells were ringing, and of using paper index cards to log patched calls for billing.

During the 1940s, when my mother operated the switchboard in Silver Lake, my father occasionally operated the Winsted switchboard.

They would talk with each other while patching calls between the two towns; they were married April 14, 1951.

In 1947, AT&T, along with the Bell System and independent telephone companies, developed the North American Numbering Plan (NANP).

This plan standardized telephone numbering, eventually leading to the development of direct distance dialing (DDD).

New Jersey was assigned to area code 201, and Winsted, 612.

Although the NANP would enable DDD, individual customer dialing was not yet available.

Significant upgrades to the telephone network were necessary to achieve DDD, including the implementation of Multifrequency (MF) signaling and automated toll switching equipment.

AT&T’s Long Lines division began installing relay-logic toll-switching equipment to manage calls that included area code prefixes, which enabled the expansion of DDD.

Operators switching from using rotary dials to MF pushbutton keypads significantly reduced the time it took to process long-distance calls.

After receiving the number to be called, an operator keyed in the digits using the MF keypad, which transmitted them to the telephone company’s toll office’s “sender equipment,” which processed the digits for automatic routing to their destination.

Note: MF signaling is different from what is used with your pushbutton touchtone phone, which sends DTMF (dual-tone multi-frequency) digit signaling.

MF was not used on the subscriber’s telephone; around 1962, the Western Electric No. 5 Crossbar underwent modifications to process DTMF digits.

The No. 5 Crossbar system was using MF signaling for trunk-to-trunk calls between telephone exchanges.

Up until Nov. 9, 1951, individual telephone subscribers were still unable to dial long-distance calls directly from their phones, but that was about to change.

A historic first in telecommunications occurred at 1 p.m. Saturday, Nov. 10, 1951, when Mayor Melvin Leslie Denning of Englewood, NJ, completed the first coast-to-coast, direct-distance-dialed telephone call without operator assistance.

The call was made to Mayor Frank P. Osborn in Alameda, CA, from a rotary dial telephone on a desk in the central telephone switching room at the New Jersey Bell offices in Englewood.

Denning dialed Mayor Osborn’s 10-digit phone number, starting with area code 415 (Oakland/Alameda).

Note: In the early to mid-1960s, the “1” prefix became necessary for long-distance dialing to resolve call routing conflicts because the first three digits dialed could be interpreted either as an area code (NPA) or a local telephone exchange office code (NXX).

For instance, if a customer in the 612 area code dialed 218-xxxx, the telephone network would not be able to distinguish whether it was a local call within the 612 area code or a long-distance call to the 218 area code.

By the way, 612-218 is a real NPA/NXX for the Twin Cities.

The “1” prefix allowed telephone switching equipment to differentiate between 10-digit long-distance calls and 7-digit local calls within a central office exchange.

But I digress.

Denning’s call was processed through a modified Western Electric No. 5 Crossbar switching system equipped for automatic digit analysis and routing, along with automatic message accounting (AMA), a paper-tape billing system used to track the call’s details.

About 18 seconds after Mayor Denning placed his call to Alameda, Mayor Osborn’s phone rang.

Upon answering, Osborn heard Denning ask, “Hello. How’s the weather out there?”

“Fine,” Osborn replied and joked if it is true that “people in New Jersey ride mosquitoes the same as we ride horses out here?” to which Denning chuckled – direct distance dialing’s journey had truly begun.

“The Nation at Your Fingertips” is a 1951 Library of Congress video (https://archive.org/details/the-nation-at-your-fingertips-1951) of an AT&T promotional film on telecommunications in Englewood, NJ.