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Contents

README

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TD501M485

VISOM · RS485 Bus Modules · DIP-8

TD501M485 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 RXD output UART receive data output to the host MCU (data received from the RS-485 bus). CMOS logic referenced to VCC (5 V for TD501M485); VOH >= VCC-0.4 V and VOL <= 0.4 V at 4 mA. Maximum output current 10 mA. Not compatible with a 3.3 V host.
2 TXD input UART transmit data input from the host MCU (data sent onto the RS-485 bus). CMOS logic input referenced to VCC (5 V): VIH >= 0.7VCC, VIL <= 0.3VCC. Drive current 2 mA typical. Automatic transmit/receive switching, no external DE/RE control required.
3 GND power_in Primary-side (input / logic) ground return for VCC and the TXD/RXD UART interface. Galvanically isolated from RGND on the RS-485 side (2.5 kVDC isolation).
4 VCC power_in Primary-side supply input, 5 V nominal (4.75-5.25 V) for TD501M485. Absolute maximum 7 V; module has no reverse-polarity protection. Static current ~18 mA typ, max operating current 70 mA. Bypass with 10 uF close to the pin.
5 RGND power_out Secondary-side (isolated) ground reference for the RS-485 A/B bus and for the internal isolated VO rail. Galvanically isolated from GND (pin 3) by 2500 VDC. For enhanced EMC, connect RGND to the cable inner shield with the outer shield single-point earthed.
6 A bidirectional RS-485 non-inverting differential bus line (A). Isolated from the primary side. Differential output
7 B bidirectional RS-485 inverting differential bus line (B). Isolated complement to pin A. Same electrical characteristics as A. Receiver input impedance >= 96 kohm over -7 V <= VCM <= +12 V.
8 VO power_out Isolated output rail from the internal DC-DC (regulated on the secondary side, referenced to RGND). Available as an auxiliary supply for external protection/bias networks on the RS-485 side; do not use to power large external loads. Leave open if unused.

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

  • TD501M485
  • TD501M485TD301M485

CAD (KiCad official)

  • Symbol: TD501M485
  • Footprint: Package_DIP:DIP-8_W7.62mm
  • 3D model: DIP-8 (KiCad packages3D, STEP)

Provenance

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

  • Datasheet: VISOM datasheet (5 pp, sha256 0a59d57775f819bf, 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