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fostc  b&b logo

High Speed Fiber Modem Converter RS-232/422/485

US Prices
CDN Prices

Privacy and Security Policy

General Product Information

Model FOSTC provides the most versatile connection possible between any asynchronous serial equipment using fiber optic cable. It allows any two pieces of asynchronous serial equipment to communicate full or half-duplex over two fibers at typical distances up to 2.5 miles. The converter can also be used to create a multi-drop master/slave configuration, allowing one serial device to talk to multiple slave devices around a fiber ring. RS-232, RS-422, or RS-485 data signals are supported. Different standards can be mixed and matched to allow RS-232 devices to connect to your RS-422 or RS-485 system. This means the FOSTC can replace converters and isolators when connecting remote devices, while providing the EMI/RFI and transient immunity of optical fiber. Supports both the Transmit and Receive data lines, and provides full hardware control of the RS-485 driver with B&B's automatic Send Data control circuit. All serial connections are provided on the same DB25 female connector, while the multimode fiber is connected via two ST connectors. Powered by 12 VDC at 140 mA max. A power supply is available.

Features and Details

  • Asynchronous RS-232, RS-422, or RS-485 operation
  • Full or half-duplex
  • Automatic Send Data Control of RS-485 driver
  • RS-232 data rates to 115.2 kbps; RS-422/485 rates to 460 kbps
  • Typical range up to 2.5 miles on multimode glass fiber
  • EMI/RFI and transient immunity
  • ST connectors
  • Modbus compatible
  • Compatible with B&B Model FOSTCDR


Power Range AC: 0 to 0 Temp Range: 0 to 55
Mounting / Packaging: In Line UL: No
Class 1 Division 2: No Modbus: No
Automatic Send Data Control: Yes Power Range DC: 12 to 12
Power Source: External Power Max AC: No
RS-232: No RS-422: No
RS-485 2 Wire: Yes RS-485 4 Wire: Yes
TTL: No Current Loop: No
Multi-mode Fiber: Yes Single Mode Fiber: No
Isolation: Yes 3-Way Isolation: No
Brand: B&B Electronics  

Buy FOSTC on-line:
USA Office

Address: 1480 Gulf Road, Suite 837,
PO Box 1364
Point Roberts, WA 98281

Western Canada - Vancouver BC

Tel:1.800.663.6001 or 1.604.925.6150
Address: 2454 Haywood Ave
West Vancouver, BC V7V 1Y1

Eastern Canada - Markham, Ontario

Tel:1.800.465.0164 or 1.905.513.7027