Switchcraft

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1/4" LONG FRAME TELEPHONE JACKS

click here to download a schematic drawing
(you will need to have Adobe Acrobat installed on your system to do this)

JACK MATERIALS

The complete Switchcraft line of standard size panels, jacks, plugs, switches and accessories are rugged, premium quality devices...hand-crafted by experts...100% inspected...and carefully adjusted to meet the traditionally high quality demands of the telephone industry and the military. Tightly controlled incoming inspection, manufacturing methods, and QC procedures assure you of long-life, reliable components. Typical applications where Switchcraft components have been specified for more than five decades are: telephone central office equipment, switchboards, jackfields, test and patch panels, and station equipment; TV and radio broadcasting consoles; PA and communication consoles; telegraph systems and apparatus; multichannel video and audio patching; and data processing equipment, such as computers, telemetry, I/O devices and facsimile.
FRAMES  Jack frames are heavy steel, formed and press welded for added strength. Side member adds to frame rigidity and resistance to shock and vibration. Both "A" and "C" type frames can be supplied. (See next page.)
SPRINGS  A special copper alloy is used for leaf springs because it offers excellent mechanical and electrical characteristics, and good corrosion resistance. The spring alloy has special hardness and ductility, and springs are produced from custom-designed dies. Although normally adjusted to mate with telephone (and MIL-type) plugs, springs can be adjusted to mate with commercial phone plugs.
BUSHINGS Bushings are a copper alloy (except insulated jacks), drilled to accept either a standard (.250 inches diameter finger) plug or a popular smaller (.206 inches diameter finger) plug. Series M Hi-D Jax have a threaded brass bushing, or a molded thermoplastic bushing for insulated mounting.
CONTACTS Jack design includes "wiping" action of contacts for low resistance connections. The contacts supplied depend on the jack selected. Gold or silver plating is normally offered as an option on tip, ring and/or sleeve springs. Several precious metals and shapes are used on jacks.

Material
Shape Description

Palladium Welded Crossbar Best overall combination of life, current carrying, and resistance
to environment. Also known as WEco #2.

Fine silver
Riveted, button-type
Carries higher current than palladium.

Gold alloy
Welded Crossbar Recommended for dry circuit switching. Excellent resistance to
corrosion and contamination.
Also known as WEco #1.

Fine silver (Large) Riveted,
button-type
Heavy currents.

Gold or Silver Plating For lower contact resistance
(used on through circuit springs).

SOLDER LUGS TERMINALS Lugs project out directly from rear of jack and are solder-coated for easy wiring and soldering. Offset lugs can be supplied on special order (except standard on MT-Jax®). Jacks with offset ground lugs are particularly suitable for bussing connections on jack panels. Contact Switchcraft for special order lug requirements.
WIRE-WRAPPING TERMINALS Wire-wrapping eliminates the need for soldering. Each terminal accepts up to three wrapped wires (22 or 24 gauge, 5 wraps each), applied with standard wire-wrapping tools. Terminal base has standoff shoulder which prevents first wrapped wire from accidentally sliding down and shorting against another terminal or adjacent spring. Terminal tips are radiused to facilitate positioning of wire-wrapping tool over terminals. See page 65 for wire-wrapping data.
PRINTED CIRCUIT TERMINALS Components can be supplied with printed circuit terminals on special order. Terminals can be specified in various lengths to accommodate different thicknesses of single and double sided boards, as well as multilayers, and flat flexible cable and circuitry.
OTHER TERMINALS Many other special terminal styles are possible. For example, where mounting permits, jacks can be supplied with stacks having right-angle terminals. Contact Switchcraft for special terminals.
CUSTOM COMPONENTS
Only the most popular types of jacks are listed.

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Material	Shape	Description
Palladium	Welded Crossbar	Best overall combination of life, current carrying, and resistance to environment. Also known as WEco #2.
Fine silver	Riveted, button-type	Carries higher current than palladium.
Gold alloy	Welded Crossbar	Recommended for dry circuit switching. Excellent resistance to corrosion and contamination. Also known as WEco #1.
Fine silver (Large)	Riveted, button-type	Heavy currents.
Gold or Silver	Plating	For lower contact resistance (used on through circuit springs).