Couplers

Working knuckle couplers are a closer approximation to the "automatic" couplers used on the prototype there and elsewhere.

Acoustic couplers are still used by people travelling in areas of the world where electrical connection to the telephone network is illegal or impractical.

Acoustic couplers were sensitive to external noise and depended on the widespread standardization of the dimensions of telephone handsets.

As early as 1937, telefax machines used by newspapers were using some kind of couplers, possibly acoustic but more likely magnetic for single-directional communication.

But in a color film, the by-products of the development reaction simultaneously combine with chemicals known as color couplers that are included either in the film itself or in the developer solution to form colored dyes.

Directional couplers can be used at HF through microwave frequencies and respond only to waves travelling either in the forward or reverse direction.

Early modems were generally very simple devices using acoustic couplers to handle telephone operation.

Emulsion The emulsion consists of silver halide grains suspended in a gelatin colloid; in the case of color film, there are three layers of silver halide, which are mixed with color couplers and interlayers that filter specific light spectra.

For British modellers, whose most popular scale is OO, the normal coupler is a tension-lock coupler, which, again has no pretence of replicating the usual prototype three-link chain couplers.

In all scales couplers can be exchanged, with varying degrees of difficulty.

None of the popular couplers has any resemblance to the prototype three-link chains generally used on the continent.

Other scales have similar ranges of non-compatible couplers available.

The color couplers in the blue-sensitive layer will form yellow dye during processing, the green layer will form magenta dye and the red layer will form cyan dye.

This arrangement provides a secure connection, but allows the couplers to break away without damaging the equipment if they are pulled, as may happen when the tractor and trailer are separated without first uncoupling the air lines.

Trains can be lengthened by coupling two TGVs, using couplers hidden in the noses of the power cars.