Solid State
Building Entrance 5Pin Modules

3B1S-300 & 3B1FS-240, 4B1S-300 & 4B1FS-240

Balanced Operation





The 3B1S-300 & 3B1FS-240 premium series 5-pin solid-state protector modules are designed to provide superior transient and power fault protection for most standard telephone line applications.  These solid-state  modules are particularly suited to applications that require the protection of very sensitive digital equipment due to their nanosecond reaction time.  The balanced configuration of these modules provides the best protection against a line-to-line, metallic surge, where there is a large voltage differential between the two sides of the circuit.  The characteristics of the solid-state protector are far superior to gas tube technology in speed of response and are virtually immune to overshoot, aging, and failure due to repeated tripping within rated limits.  

The 4B1** series features PTC (positive temperature coefficient) technology.  These optional self-resetting current limiters provide effective protection from sneak current faults.  The PTC is vastly superior to the competition's heat coil solution which requires that the module be replaced after each sneak current event.


bulletsolid state technology provides nanosecond response time
bulletexternal failsafe mechanism that permanently grounds module under sustained high current conditions Ľ safe mode operation in adverse situations
bulletdesigned to meet or exceed Telcordia standards 
bulletUL & cUL listed Ľ documented safe performance
bulletIntegrated Test Points 



bulletreduced "pass through" of dangerous transients
bulletlonger lifespan than conventional gas tube and carbon arrestors
bulletsafe mode operation in adverse situations
bulletreduced service calls
bulletdocumented safe performance
bulletISO 9002 Certified Manufacturer


Ordering Information

Model No. Order No. Pin1 Color
3B1S-300 750029 Gold Black
3B1FS-240 750033 Gold Black
4B1S-300 750031 Gold Black
3B1FS-240 750036 Gold Black

1pin allow refers to tip and ring pins.  Unless otherwise noted, all ground pins are tin.





*B1FS-240 *B1S-300


  DC Breakdown (nominal)






1Vrms@1KHZ, 50VDC



  Peak Pulse Current (max)11


  Insulation Resistance


 @ 8 x 20 Ásec 




>100M ohms

@ 10 x 160 Ásec 



@10 x 1000 Ásec



Fail-safe Operation


@1.0 A

<50 sec

  Holding Current (mA)



 @5.0 A

<15 sec


@20 A

<10 sec

Surge life
(min operations)2


@60 A

<3 sec

@10A, 10 x 1000 Ásec



@100A, 10 x 1000 Ásec



@1Arms, 1 sec



@10 Arms, 1 sec



1total surge rating is 2x listed with respect to ground during a simultaneous surge
2service life requirement as per Bellcore TR-NWT-000974

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