Product Description

The Bismon B1-DV1DS-20A/B is a cost-effective RS232/RS485/RS422 to fiber optic converter for reliable long-distance serial communication.
It transmits and receives data over a single fiber core using WDM (Wavelength Division Multiplexing) technology.
The units work as a matched pair: A side transmits 1310nm / receives 1550nm and B side transmits 1550nm / receives 1310nm.
This saves 50% of fiber cores, making it ideal for existing cables with limited spare cores or leased fiber billed per core.
It supports a transmission distance of up to 20km over single-mode fiber, with a 40km version (B1-DV1DS-40A/B) available.
All three serial interfaces (RS232, RS485 and RS422) are available on one 8-pin terminal block for easy field wiring.
Automatic signal rate detection and zero-delay transmission let it work with existing serial equipment without any configuration.
Built-in 1500W surge and 15kV ESD protection, together with the fiber link, guard equipment against lightning, surges and electromagnetic interference.
It runs on a wide 9–40V DC power input and comes in a compact iron housing with wall-mount ears.
It is ideal for connecting RTUs to host or SCADA systems, solar cell systems (inverters, smart meters, data loggers), PLCs and industrial monitoring.

Why Choose Single-Fiber for RS485 to Fiber Systems?

• -Saves 50% of fiber cores: one core per link instead of two, which frees up capacity in existing cables.
• -Lower operating cost: leased dark fiber is often billed per core, so a single-fiber link costs half as much.
• -Fits low-bandwidth serial data: RS485 traffic is small, so dedicating two cores to it wastes cable capacity.
• -Easy expansion: the same cable can carry twice as many serial links.
• -Simpler installation: one connector per side and no risk of swapping TX/RX fibers.
• -Fewer loss points: fewer connectors and splices give a more stable optical link.
• -Note: units must always be installed as an A + B pair.

Features

• -Single-fiber WDM (BiDi) transmission over one single-mode fiber core
• -A/B paired operation: A side 1310nm/1550nm, B side 1550nm/1310nm
• -Supports RS232, RS485 and RS422 interfaces
• -Asynchronous point-to-point communication
• -Automatic signal rate detection with zero-delay transmission
• -RS485/422 supports 32 nodes (128 nodes available on request)
• -Transmission distance up to 20km (40km version available)
• -Wide 9–40V DC power input, 2W consumption
• -1500W surge protection and 15kV ESD protection
• -Compact iron housing with wall-mount ears

Functions

• -Serial to fiber conversion: converts RS232/485/422 electrical signals into optical signals over fiber.
• -Transparent transmission: passes data without changing the protocol, so Modbus RTU and other serial protocols work directly.
• -Wavelength multiplexing: separates the transmit and receive directions on one core using 1310nm and 1550nm.
• -Auto rate detection: matches the serial data rate automatically, with no manual setup.
• -Interface conversion: connects devices with different serial standards, for example RS232 on one side and RS485 on the other.
• -Status monitoring: Power, RxD and TxD LEDs show power and fiber link activity.

Benefits

• -Reduces fiber, splicing, connector and leasing costs
• -Reuses existing fiber cables that have few spare cores
• -Extends RS485/RS232 communication far beyond copper cable limits
• -Isolates grounds between sites to prevent ground loop problems
• -Protects equipment from lightning, surges and EMI
• -Works with existing SCADA, PLC and solar monitoring systems without software changes
• -Quick installation with terminal block wiring and no configuration
• -Improves data security, because fiber is far harder to tap than copper