Trimline telephone


The Trimline telephone is a series of telephones produced by Western Electric, the manufacturing unit of the Bell System, and first introduced in 1965. It was designed by Henry Dreyfuss Associates under the project direction of Donald Genaro; the firm had designed all previous desktop telephone models for the American Telephone & Telegraph conglomerate.

History

After the introduction of the popular Princess telephone line, in 1959 and the early 1960s, the design motivation for the Trimline series was to create an alternative design that was stylish and easier to use than a traditional telephone. This was accomplished by moving the dial from the telephone's base to the underside of the handset, between the earpiece and mouthpiece. The same concept was later used for cellular telephone and cordless telephone models. To miniaturize the rotary dial sufficiently to fit in the Trimline handset, the designers invented an unusual moving fingerstop. Like in the Princess line, the dial was lit when the handset was removed from the base. The Trimline was also one of the first phones to use the predecessor of the now-ubiquitous RJ11 modular phone plug and jack.
First introduced in 1965, the Trimline included a lighted dial and was encased in a sleek, curved plastic housing that took up much less space than earlier Western Electric telephones. However, the glass-smooth and shallowly-curved plastic handset proved difficult to retain between cheek and shoulder for hands-free communication without slipping, and this problem was never corrected over the life of the model line. Cushioned clamp-on adaptors were manufactured and sold by third parties to make it easier to cradle the handset, but these add-ons would greatly compromise the aesthetic appearance of the telephone.
The first Trimline models used incandescent dial lights powered by a power transformer plugged into a standard 120VAC outlet. The bulky transformer and the need for a conveniently-placed 120-volt outlet was criticized by many consumers, but was necessary because of the power demands of the incandescent light bulb. Years later, Western Electric redesigned the Trimline to use a low-power green LED backlit dial powered by current from the phone line, eliminating the need for a separate transformer. Always eager to re-use its older stocks of turned-in rental phones, AT&T later repainted and sold early-model non-LED Trimlines as "non-lighted" models, without a transformer.

Variants

The Trimline handset was produced in both rotary dial and Touch-Tone versions. Rotary dial Trimline production began in late 1965 and Touch Tone dials were added the following year in mid-1966. The Trimline base was available in desk-top and wall-mount versions. The handsets and bases were interchangeable. The Trimline was the first US telephone to achieve some design recognition in Europe, where it was referred to as the "Manhattan" model or the "Gondola". Today, similarly designed telephones are sold by many companies. AT&T retained the Trimline name for the later "Trimline III", a more compact successor featuring squared corners and straight lines.
In the 21st century, Advanced American Telephones produces the Trimline models 205, 210, and the 265, under license from AT&T.

Powered RJ11 jacks for illumination

In the Trimline version designed for connection to an RJ11 telephone jack, pins 2 and 5 may carry very low voltage AC or DC power. While the phone line itself supplies enough power for most telephones, older telephone instruments with incandescent dial lights in them needed different voltages and more current than the phone line could supply. Typically, the power on pins 2 and 5 came from a transformer plugged into a power outlet near one telephone jack, wired to supply power to just that telephone. It is now usually recommended that only the one local jack used by such older telephones be wired for power, to avoid any potential interference with other types of service that might be using pins 2 and 5 in jacks in other parts of the house. The early Trimline and Princess phone dial light incandescent lamps were rated at 6.3 Volts, 0.25 Amp and the transformer output is approximately 6-8 Volts AC. Later Trimline versions had LED light sources, powered directly from the phone line, and the last Western Electric-made Princess version had no dial light.

Timeline