component

RSM485CT

Public Made by Adom

by adom

VISOM RS485 Bus Modules, DIP-8. Datasheet-verified pinout, KiCad symbol/footprint/3D.

componentiot-communication modulesrsm485ct
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Contents

README

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RSM485CT

VISOM · RS485 Bus Modules · DIP-8

RSM485CT from VISOM, in a DIP-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 VCC power_in Power supply input positive. 5V nominal (4.75V-5.25V) for RSM485CT. Typical quiescent current 28 mA, max operating current 130 mA. Absolute max input voltage 7V; no reverse-polarity protection.
2 GND power_in Power supply input ground. Reference for VCC and the primary/UART side (TXD, RXD, CON). Galvanically isolated from RGND (2.5 kVDC isolation).
3 TXD input UART transmit data input from host MCU. 5V logic (VIH ≥ 0.7·VCC, VIL ≤ 0.3·VCC). Internal 10 kΩ pull-up; drive current 2 mA. Data on TXD is transmitted onto the A/B bus when CON is low.
4 RXD output UART receive data output to host MCU. Push-pull output (VOH ≥ VCC-0.4 V, VOL ≤ 0.4 V at 4 mA), max output current 10 mA. Reflects the A/B bus differential state when CON is high.
5 CON input Transmit/receive direction control. CON=0 (low) → transmit mode (drives A/B from TXD); CON=1 (high) → receive mode (drives RXD from A/B). Note: polarity is inverted from a standard RS-485 transceiver's DE/RE. VIH ≥ 3.8V (RSM485CT), VIL ≤ 0.3·VCC. Drive current 5 mA.
8 B bidirectional RS-485 differential bus line B (inverting). Internally biased with 22 kΩ pull-down/up network; integrated ESD protection. Differential output voltage
9 A bidirectional RS-485 differential bus line A (non-inverting). Internally biased with 22 kΩ pull-down/up network; integrated ESD protection. Paired with B to form the isolated RS-485 differential bus.
10 RGND power_out Isolated output-side ground (secondary side reference for the A/B RS-485 bus). Galvanically isolated from GND (pin 2) by 2.5 kVDC. May be left floating if not used; in noisy environments connect to cable shield / earth through impedance network per §9.5.

Key specifications

Parameter Value
Manufacturer VISOM
Package DIP-8
Category IoT/Communication Modules
Pins 8

Ordering variants

Same part, different packaging or reel option.

  • RSM485CT
  • RSM485CTRSM3485CT

CAD (KiCad official)

  • Symbol: RSM485CT
  • Footprint: Package_DIP:DIP-8_W7.62mm
  • 3D model: DIP-8 (KiCad packages3D, STEP)
  • 3D model files: rsm485ct-etched.step / rsm485ct-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); rsm485ct.step / rsm485ct.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: VISOM datasheet (5 pp, sha256 ca9943a215648f36, retrieved 2026-08-17, tier: lcsc)
  • Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF