Black Box Opto Isolators

Stop Ground Loops of Up To 2500 Volts from Wreaking Havoc

Low Price Guarantee


What's special about these ground loop isolators?

  • Protects your computer and your data from ground loops using an internal fiber optic air gap
  • Saves you $1000’s in maintenance and repairs as well as downtime created by ground loop surges
  • Converts data signals into light pulses that continue along the circuit harmlessly
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Linking two devices powered by separate AC sources can create potential ground-loop surges that can damage your computer systems and wipe out data.


BB-SP340A-R3 High Speed Opto Isolator 0.8" H x 2.1" W x 3.8" D
(2 x 5.3 x 9.7 cm)
0.8 lb
BB-SP401A RS422 / RS485 Opto Isolator 1" H x 2.3" W x 2.3" D
(2.5 x 5.8 x 5.8 cm)
0.1 lb
  • You can choose from three different devices according to your needs:
    • High-speed Opto Isolator to protect devices with 115.2-kbps serial ports up to 1000 ft on either side of the interface
    • RS-422/485 Opto Isolator protects RS-422/485 lines up to 2000 ft
  • 3 years Double Diamond Protection for the High-speed Opto Isolator
  • 1 year Double Diamond Protection for the Opto Isolator II, and RS-422/485 Opto Isolator


The Black Box Opto Isolators help protect your computers by stopping ground loops of up to 2500 volts from destroying your system. Inside the Opto Isolators data signals are converted to light pulses using an internal fiber optic link. These pulses then continue along the circuit as light to saves you $1000’s in maintenance and downtime.

  SP340-A-R3 SP401A
Protocol Asynchronous Asynchronous
Speed Up to 115.2 kbps Up to 19.2 kbps
Interface RS-232 RS-22/485
Connectors (1) DB25 F (1) DB25 M (2) RJ-45
Power From the interface or optional 120-VAC Wallmount Power Supply (PS1002) From the interface or optional 120-VAC Wallmount Power Supply (PS1002)
Operating Temperature 0° - 70° C 0° - 70° C
Dimensions 0.8" H x 2.1" W x 3.8" D (2 x 5.3 x 9.7 cm) 1" H x 2.3" W x 2.3" D (2.5 x 5.8 x 5.8 cm)
Weight 0.8 lb (0.4 kg) 0.1 lb (<0.1 kg)


The Double Diamond Warranty is our no-questions-asked warranty that protects your BLACK BOX® brand products from accidental damage, including drops, water, and power surges. Most products come with a one- or two-year warranty. Some products, such as copper cables, manual switches, cabinets, and racks, are guaranteed for life! During the warranty period, Black Box will repair or replace your damaged equipment within one week of receipt at NO CHARGE!







APC Back-UPS ESAPC Back-UPS ES 8 Outlet 550VA 120V
Best Value For Home and Small Office Battery Backup Protection. Protects electronic devices and up to 2 data lines (RJ-11, fax or DSL) from power surges up to 365 Joules

APC Smart-UPS 750VAAPC Smart-UPS 750VA LCD
Prevents Critical Data Loss in Servers and Network Equipment When Power Failure Strikes. Automatically self-tests so you can maintain quality of protection. Run time is up to 15.9 minutes (at half-load capacity)

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