"MOBILE TELEPHONES" 1940s BELL TELEPHONE MOVIE EARLY CELL PHONE / MOBILE TELEPHONE SYSTEM 90884

Video Description

Created in the late 1940s, this film "Mobile Telephones" from Bell explains the operation of the Mobile Telephone Service (MTS) by showing how it can be used to make business more efficient. The film also shows some of the cutting edge equipment used in the system and shows how it was installed in vehicles (7:30). MTS was a pre-cellular VHF radio system that linked to the Public Switched Telephone Network (PSTN). As such it used both radio signals and telephone lines to connect parties. MTS was the radiotelephone equivalent of land dial phone service. It was operator assisted in both directions, meaning that if one were called from a land line the call would be routed to a mobile operator, who would route it to one's phone. Similarly, to make an outbound call one had to go through the mobile operator, who would ask for the mobile number and the number to be called, and would then place the call. This service originated with the Bell System, and was first used in St. Louis on June 17, 1946. The original equipment weighed 80 pounds (36 kg), and there were initially only 3 channels for all the users in the metropolitan area, later more licenses were added bringing the total to 32 channels across 3 bands This service was used at least into the 1980s. Due to the small number of radio frequencies available, the service quickly reached capacity. MTS was replaced by Improved Mobile Telephone Service (IMTS), introduced in 1964. 0:00 – A truck drives along a remote highway, emphasizing the challenge of communicating with vehicles far from towns and regular telephone lines. 0:54 – A dispatcher uses mobile telephone service to call a moving truck using its unit number; the driver answers promptly, and they arrange a new pickup for the Ajax Company at Charleston Depot. 1:28 – The truck drivers receive the instructions clearly and reroute by turning onto Route 117, demonstrating how quickly mobile communication enables logistical adjustments. 1:52 – At a construction site on the outskirts of a city, a foreman uses mobile telephone service to report equipment trouble to the main office; the issue is discussed and a mechanic is dispatched. 2:54 – The narrator begins a technical explanation: mobile telephone service works by combining radio transmissions with landline telephone networks to reach moving vehicles. 3:50 – A dispatcher initiates a call to a mobile unit by using a regular business telephone and dialing long distance through a telephone operator. 4:39 – The call reaches the Centerville base station, which broadcasts it via radio; the truck’s radio unit picks it up and responds, completing the two-way connection. 5:03 – Frequency modulation (FM) is used for the radio segments of the call, ensuring clear, high-quality voice transmission between the base station and mobile units. 5:17 – A second type of mobile telephone system is introduced, designed for both urban and intercity use, expanding the reach of this communication technology. 6:00 – Outgoing calls from vehicles are transmitted to the nearest antenna, routed by telephone lines to a central base station, and then handled like any regular phone call. 6:35 – Reply messages from the base station are broadcast city-wide via a powerful central transmitter, ensuring they reach mobile units anywhere within the coverage area. 7:01 – The push-to-talk mechanism is explained: users must press a button to transmit and release it to listen, making communication simple but deliberate. 7:22 – Installation of the equipment is shown in detail: transmitter and receiver units fit neatly in a vehicle, with the antenna placed on the roof or rear side of a truck. 8:00 – When a call comes in, signal lights and a ringing bell alert the user; if missed, the indicator remains lit until the user returns and calls the mobile operator. 8:27 – The video demonstrates base station operations: antennas receive calls, which pass through receivers and are routed via control terminals to a switchboard. 9:00 – The return leg of the call travels back through the central office to a transmitter, then over the air to the intended vehicle, completing the communication loop. 9:17 – A nationwide network of mobile telephone stations is being developed to link vehicles and people across the U.S., enhancing voice communication access. 9:34 – The benefits of mobile communication are highlighted: smoother operations at railway terminals, better coordination on waterways, convenience for travelers, and efficient highway logistics. 9:58 – The film concludes by emphasizing that mobile telephone service is a major step toward universal connectivity—making it possible to reach anyone, anytime, anywhere. This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. For more information visit http://www.PeriscopeFilm.com