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

BH #SWMT389 • MFR #MT389
Switchcraft 3-Conductor 1/4" Long-Frame Telephone Twin Jack
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Expected availability: 2-4 weeks
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Switchcraft MT389 Overview

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.

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

Switchcraft MT389 Specs

FrameFrame and Stack Screws: Steel, plated with iridescent iridite finish
SpringsCopper alloy, spring tempered
Solder lugs are solder coated
BushingNickel-plated copper alloy
ContactsWelded crossbar palladium in shunt circuits
InsulationRigid plastic (MIL-type PBE-P, per MIL Specification LP-513C)
Extruded plastic insulating tubing through stack
Contact Resistance10-MOhm maximum (initial), 20-MOhm maximum (after life), 100-MOhm maximum (after salt spray)
Insulation Resistance10,000-MOhm minimum (initial), 1,000-MOhm minimum (after humidity, durability exposure)
Dielectric Withstanding Voltage Test500 VAC, 60 Hz (rms)
Temperature RangeOperating: -40 to 149°F (-40 to 65°C)
Non-Operating: -67 to 185°F (-55 to 85°C)
Shock ResistanceThermal: Per MIL-STD-202, method 107
Humidity0 to 95% operating/non-operating
Salt SprayPer MIL-STD-202, method 101 (48 hours)
Moisture ResistanceMIL-STD-202, method 106 (240 hours)
CertificationUL recognized
Number of Conductors3
CompatibilityAdjusted for WEco type 310 MIL types M642/2-1 and M642/2-2 plugs
Life Expectancy20,000 insertion/withdrawal cycles, minimum
ShockPer MIL-STD-202, method 213, Test Condition H (75 g)
VibrationPer MIL-STD-202, method 213, (10 to 55 Hz)
MountingFrame mounting ears are on 1.375" (34.9 mm) centers
Bushings are on 0.625" (15.9 mm) centers
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