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Green rectangular circuit board with terminal blocks and pin headers

BFKK

BFKK 2-in-1 RS485/TTL232 4-Ch MOS 8-Ch TTL Output Module

SKU CH-3YVR-S6554

Combines RS485 and TTL232 interfaces with four 3A MOS transistor outputs and eight 5V TTL outputs controllable via AT or Modbus RTU commands

  • Dual RS485 and TTL232 interfaces operate simultaneously
  • Four MOS transistor outputs drive up to 3A each for relays and motors
  • Eight 5V TTL outputs default to low-level NPN with optional high-level PNP setting
  • Supports both AT and Modbus RTU commands with up to 247 devices in parallel
  • Compact 96.5 x 35 x 15 mm module weighs only 27 grams

Dual-interface relay module

The BFKK 2-in-1 RS485/TTL232 module provides four MOS transistor outputs rated at 3 A and eight 5 V TTL outputs for industrial control. It accepts DC 6-25 V supply and draws 10-15 mA quiescent current. Both serial interfaces operate independently and simultaneously, allowing mixed AT-command and Modbus RTU networks. The compact 96.5 × 35 × 15 mm board weighs 27 g.

Sustained-load behaviour

Under continuous operation the supply must exceed twice the total load power, or three times for inductive loads such as relays or solenoids. Each MOS channel handles 3 A NPN low-level switching, while the eight TTL channels supply 10 mA default low-level output, configurable to high-level PNP by command. Up to 247 modules can share a Modbus RTU bus without address conflicts.

Installation notes

Wiring uses the dual RS485 and TTL232 ports; both can be connected at once for redundant or parallel control paths. The M0 pads are factory-bridged, locking the module into Modbus RTU mode and disabling AT-command switching unless the bridge is removed. Delay commands accept 0.1-9999.9 s resolution, and supported Modbus function codes are 01, 03, 05, 06, 15, 16.

Highlights

  • Dual RS485 and TTL232 interfaces operate simultaneously
  • Four MOS transistor outputs drive up to 3A each for relays and motors
  • Eight 5V TTL outputs default to low-level NPN with optional high-level PNP setting
  • Supports both AT and Modbus RTU commands with up to 247 devices in parallel
  • Compact 96.5 x 35 x 15 mm module weighs only 27 grams

Specifications

No published specifications for this item yet.

Questions about this item

Does the 4-channel MOS transistor output generate much heat when driving 3 A loads continuously?

The module draws only 10-15 mA itself; each MOS channel handles up to 3 A. Keep the supply at least twice the load power, or three times for inductive loads, to maintain stable operation.

What power supply must I already have to run this module?

A DC source between 6 V and 25 V that can deliver at least twice the total load power, or three times for inductive loads such as relays or motors.

Can I keep using my existing Modbus RTU network with 247 devices when I add this module?

Yes, in Modbus RTU mode the module supports up to 247 devices on the same bus and works with function codes 01, 03, 05, 06, 15 and 16.

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