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Switchcraft 3-Conductor 1/4" Long-Frame Telephone Twin Jack

Switchcraft 3-Conductor 1/4" Long-Frame Telephone Twin Jack

B&H # SWMT389 MFR # MT389
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Expected availability: 7-10 business days
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You Pay: $29.50

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Switchcraft MT389 overview

  • 1Description

The Switchcraft 3-Conductor 1/4" Long-Frame Telephone Twin Jack has both the tip and ring circuits interconnected (crossover wired), so if a plug is inserted in either jack, common circuits are opened. It is used in Switchcraft Series 2400, 2600, and JP Jack Panels and other standard jack panels. The jack's solder lugs are equivalent to WEco 482A and the jack is adjusted for WEco type 310 (MIL types M642/2-1 and M642/2-2) plugs.

Note: Mounting screws (#6-32) are not included.

In the Box
Switchcraft 3-Conductor 1/4" Long-Frame Telephone Twin Jack
  • Limited Lifetime Warranty
  • Table of Contents
    • 1Description

    Switchcraft MT389 specs

    Frame Frame and Stack Screws: Steel, plated with iridescent iridite finish
    Springs Copper alloy, spring tempered
    Solder lugs are solder coated
    Bushing Nickel-plated copper alloy
    Contacts Welded crossbar palladium in shunt circuits
    Insulation Rigid plastic (MIL-type PBE-P, per MIL Specification LP-513C)
    Extruded plastic insulating tubing through stack
    Contact Resistance 10-MOhm maximum (initial), 20-MOhm maximum (after life), 100-MOhm maximum (after salt spray)
    Insulation Resistance 10,000-MOhm minimum (initial), 1,000-MOhm minimum (after humidity, durability exposure)
    Dielectric Withstanding Voltage Test 500 VAC, 60 Hz (rms)
    Temperature Range Operating: -40 to 149°F (-40 to 65°C)
    Non-Operating: -67 to 185°F (-55 to 85°C)
    Shock Resistance Thermal: Per MIL-STD-202, method 107
    Humidity 0 to 95% operating/non-operating
    Salt Spray Per MIL-STD-202, method 101 (48 hours)
    Moisture Resistance MIL-STD-202, method 106 (240 hours)
    Certification UL recognized
    Number of Conductors 3
    Compatibility Adjusted for WEco type 310 MIL types M642/2-1 and M642/2-2 plugs
    Life Expectancy 20,000 insertion/withdrawal cycles, minimum
    Shock Per MIL-STD-202, method 213, Test Condition H (75 g)
    Vibration Per MIL-STD-202, method 213, (10 to 55 Hz)
    Mounting Frame mounting ears are on 1.375" (34.9 mm) centers
    Bushings are on 0.625" (15.9 mm) centers

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