Operator assistance

thumb|300px|Bell System overseas switchboard operators during World War II

Operator assistance refers to service provided by a telephone operator to the calling party of a telephone call. This included telephone calls made from pay phones, calls placed station-to-station, person-to-person, or collect, third-number calls, calls billed to credit cards, and certain international calls which could not be dialed directly.

Operators could also assist with diagnosing technical difficulties, verifying whether a line was busy (busy line verification, or BLV), or left off the hook, or breaking in on a live call to ask the caller to clear the line for an incoming call (busy line interruption, or BLI). The latter service was often utilized by emergency police. In addition, operators were often a first point of contact for the elderly wanting information on the current date and time.

Before the advent of emergency telephone numbers, operators identified and connected emergency calls to the correct emergency services. Directory assistance was also part of the operator's job.

In the early days of telephones all calls were connected by an operator. Later, local calls could typically be dialed directly, but long-distance and international calls had to be connected by an operator, often subject to a minimum charge, typically for three minutes. Eventually it became possible to direct-dial all calls, but operator assistance continued to be available, often at higher cost, for all calls; in the US Bell System an operator-assisted call carried a 50% premium for the first three minutes.

Operator-assisted calls were initially handled at telephone switchboards which were subsequently replaced with computer assisted systems such as Traffic Service Position System (TSPS) consoles beginning in the late 1960s, which automated many aspects of call setup while still requiring operator involvement for billing verification, announcements, and customer interaction.

Connection

Station-to-station

A station-to-station call, also known as station paid or station collect depending on the billing arrangement, was an operator-assisted call in which the calling party (CLG) agreed to talk to whoever answered the telephone. Timing and billing began as soon as the call was answered, regardless of who picked up.

An operator would typically announce the call to the answering party with the phrase "(Called Party), please. Long Distance is calling."

Messenger call

When waiting for the person would exceed the holding interval, a messenger call was used. In areas with minimal telephone service such as smaller towns (and before the ubiquity of mobile phones), a call was made to a normally staffed central location with a telephone, such as a corner store, public call office, post office, or other public business, and a messenger would be hired to go to the recipient's location to advise him or her to come to the phoned location at a designated time to receive a phone call. The calling party would be advised to call the operator back at the arranged time to complete the call.

Auto Collect

The service functioned as an early form of a toll-free telephone number, enabling businesses, transportation providers, government agencies, and customer service organizations to receive inbound calls from remote locations with no charge to the caller.

Special exchange (e.g. Zenith, Enterprise, WX, Freephone)

thumb|Zenith telephone number listing in a 1938 Southern California telephone directory.

The caller requested a published or advertised number beginning with a special named exchange—such as Zenith, Enterprise, Freephone, or WX—from the telephone operator, who then looked up the destination number, completed the call, and billed the charges to the called party. The service was intended for organizations that wanted to be reachable across multiple regions without requiring local branch lines or dedicated foreign exchange circuits.

A few organizations continued to maintain auto collect numbers into the 21st century. For example, , the California Highway Patrol still published Zenith 1-2000.

Special phrase

During local events an arrangement could be made to automatically charge calls as collect with the use of a special phrase. For example, during United States elections in the early 1970s, Bell System operators applied simplified procedures for collect calls placed by reporters at polling locations to regional tabulation centers operated by the News Election Service (NES). Reporters were instructed to place calls with the phrase "NES Election Collect to [number]", eliminating the normal requirement to obtain the calling party's name or verify whether the called number was a coin telephone. The called party accepted charges with the phrase "NES — OK collect", which operators recorded as acceptance without further announcement.

Directory assistance calls were historically included in land line service but per-call charges were introduced starting in the 1970s.

The position was labor-intensive; operators at busy intercept bureaus were expected to handle multiple calls per minute and were monitored on call duration. Beginning in 1965, Bell Laboratories and Western Electric developed the Automatic Intercept System (AIS), which used stored-program controls and magnetic drum recordings to assemble and deliver customized announcements, including the dialed number and the reason for failure, without operator involvement for the majority of calls.

Early automated systems typically offered the caller the option to remain on the line for a live intercept operator after the announcement; this option was later removed as automation became more complete.

Rate and Route (R&R)

The rate and route operator was a specialized internal position consulted by telephone operators to resolve numbering and routing questions that could not be answered locally.

R&R operators could provide the area code and dialing pattern for a given city, the directory assistance routing for a given exchange, the inward operator routing for a given NPA-NXX combination, and the place name corresponding to a given office code.

International routings, including directory and inward operator access for foreign cities, were handled the same way. The position was reachable via a dedicated network route, for example the area code plus 141.

The R&R function was later supplemented by the automated Rate Quote System (RQS), a voice response system into which operators keyed routing queries and received synthesized voice responses, and was ultimately retired in 1987 when operator positions were equipped with the COMPIS computer terminal, which provided routing data directly on screen.

Special

Air-to-ground

Operators connected calls between passengers or crew on aircraft in flight and the land telephone network via VHF radio links. The first recorded scheduled service of this kind operated on the Chicago–Seattle route by Northwest Airlines in 1937.

Calls were routed through ground stations and then connected to the public switched telephone network; as the aircraft moved, coverage passed between stations. Operators handled billing verification and call completion, with the constraint that connection windows were brief and ground station coverage changed continuously with the aircraft's position. Commercial passenger air-ground telephone service expanded significantly in the 1980s with the introduction of Airfone, which provided seatback handsets on major airlines.

Conference

An operator-assisted conference call was a call with multiple parties managed by a dedicated conference operator. The telephone operator would either call participants or answer an inbound conference number which participants called, and add them to the conference — and deal with any reconnection issues. The operator might optionally gather specific information from each participant, introduce key speakers, and manage questions and answers.

Marine

Operators connected calls between vessels at sea and the land telephone network, initially via HF radio links through coast stations and later via satellite. The introduction of the MARISAT system in 1976 — three geosynchronous satellites built by Hughes Aircraft for COMSAT Corporation and positioned over the Atlantic, Pacific, and Indian Oceans, provided the first dedicated maritime satellite communications capability, supporting voice, telex, facsimile, and data between ships and shore.

Shore-based operators at coast earth stations patched satellite links to the PSTN and coordinated with international gateway operators to complete the full circuit. In 1979 the International Maritime Satellite Organization (Inmarsat) was established by 28 countries to take over and expand the service; Inmarsat assumed operational control from the Marisat system in 1981.

Military

Operators served the Department of Defense's worldwide Automatic Voice Network (AUTOVON), a parallel telephone system built from 1963 to provide the military with communications independent of the civilian PSTN. The network linked approximately 1,700 military installations globally and incorporated a multilevel precedence and preemption system allowing higher-priority calls to displace lower-priority ones on congested circuits — a capability unavailable on the civilian network.

Operators assisted with calls requiring precedence handling, connections to non-dialable military points, and bridging between AUTOVON and the civilian network. AUTOVON was replaced by the Defense Switched Network in the early 1990s.

Overseas

International calls were handled by specialized operators co-located at dedicated International Switching Centers (ISCs), which served as gateways between the domestic network and foreign telephone systems. Before the introduction of automated international dialing, all such calls required operator assistance, much as domestic long-distance calls had before Direct Distance Dialing.

The Bell System ultimately operated seven ISCs, located in White Plains, New York, Pittsburgh, Jacksonville, Oakland, Denver, and Montreal, each serving as the primary gateway to particular overseas countries with overflow connections to secondary destinations.

International operators required knowledge of foreign country routing, applicable time zones, and currency conversion for rate calculation, and coordinated with foreign operators to provide language assistance when needed. AT&T began experimenting with International Direct Distance Dialing (IDDD) as early as 1967, offering select New York City customers the ability to dial Paris and London directly; the first official IDDD service launched in May 1970, initially limited to the United Kingdom.

Radiotelephone

Operators handled calls to and from vehicle-mounted mobile telephones under the original Mobile Telephone Service (MTS), which required operator involvement in both directions: inbound calls were routed to the mobile operator who located and signaled the vehicle, while outbound calls were placed through the operator who connected to the land network. The service was labor-intensive and capacity-limited, with channels shared across a wide geographic area.

The introduction of the Improved Mobile Telephone Service (IMTS) in 1964 largely replaced operator-assisted mobile calls with direct dial, though manual mobile service persisted in some areas considerably longer, California, for example, did not fully convert to IMTS until 1982.

Relay and TDD

thumb|150px|AT&T TDD 2700

Telephone relay services allowed deaf or speech-impaired callers to communicate with hearing parties through an operator acting as an intermediary.

The caller used a telecommunications device for the deaf (TDD), also known as a teletypewriter (TTY) or textphone, to type messages over the telephone line; the relay operator voiced the typed text to the hearing party and typed back their spoken responses in real time.

The TDD itself transmitted text via frequency-shift keying (FSK) at 45.5 baud using a variant of the Baudot code, allowing only half-duplex communication. Variant services included hearing carry-over (HCO), for callers who could hear but not speak, and voice carry-over (VCO), for those who could speak but not hear. As with other operator functions, relay services were progressively supplanted by direct text communication technologies including SMS, internet relay chat, and real-time text over IP.

Telex

Bell System's Teletypewriter Exchange Service (TWX), which commenced operation on November 21, 1931, had its own operator corps handling switched text connections for business customers over dedicated lines, in a manner directly analogous to voice operator services. TWX operators connected subscribers, assisted with routing, and handled billing for text-based business calls.

The service was integrated into the Direct Distance Dialing network in 1962, reducing but not eliminating operator involvement. Western Union purchased the TWX network from AT&T in January 1969, the only major competitor to its own Telex network, and completed the conversion to its Telex II system by 1981.

Automation

Beginning in the 1960s, operator assistance functions were progressively automated through systems such as Direct Distance Dialing (DDD), the Traffic Service Position System (TSPS), and later Operator Services Position System (OSPS). These systems eliminated manual cord-switching while retaining operators for billing verification, collect-call handling, coin supervision, and specialized services.

Decline

By the late twentieth century, customer-dialed long-distance service, toll-free numbers, calling cards, cellular telephony, and automated billing systems had eliminated most routine operator functions. Many telephone companies subsequently discontinued person-to-person, collect, and third-number billing services entirely.

List of active operator assistance numbers

• Australia: 1234
• Canada: 0
• Hong Kong: 10010 (national), 10013 (international)
• United Kingdom: 100 (national), 155 (international)
• United States: 0 (domestic), 00 (international) - although no longer supported by some telephone companies