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Black DB9 female to DB9 male serial converter adapter

CoolGear

CoolGear US-232TTL33CON RS232 to TTL/CMOS Converter Adapter

SKU CH-8TJN-3KYHY

Converts RS232 signals to TTL/CMOS levels using a DB9 female-to-male adapter powered by the port itself

  • ColorBlack
  • One RS232-to-TTL/CMOS conversion in a single adapter
  • Port-powered design draws energy from the RS232 signals
  • No driver installation needed on Windows, Linux or Mac
  • DB-9 female to DB-9 male connector swap built in
  • Handles 5 V and 3.3 V logic with 115.2 Kbps throughput

Direct RS232-to-TTL/CMOS conversion

The CoolGear US-232TTL33CON adapts a standard DB-9 female RS232 port to a DB-9 male TTL/CMOS interface. It handles TxD, RxD, RTS, CTS and ground signals for legacy serial equipment. The adapter draws power directly from the RS232 line, so no external supply is needed. It works driver-free on Windows 11 down to XP, Linux and Mac OS 10.x.

Port-powered silence and negligible draw

Because the converter is powered by the RS232 signal itself, it adds no fan noise and consumes no separate mains power. Normal operation stays within the 3.3 V and 5 V tolerance range specified for the signal lines. Data rates up to 115.2 Kbps are supported without active cooling. The passive design means zero acoustic output in typical use.

Replaces bulky level-shifter boards

This single dongle replaces custom breadboard circuits or multi-component level shifters used to connect microcontrollers to a PC serial port. The jump is worth it when you need a compact, driverless link for firmware debugging or industrial device configuration. It is not suited for applications requiring galvanic isolation or voltage levels outside the stated 3.3 V and 5 V range.

Highlights

  • One RS232-to-TTL/CMOS conversion in a single adapter
  • Port-powered design draws energy from the RS232 signals
  • No driver installation needed on Windows, Linux or Mac
  • DB-9 female to DB-9 male connector swap built in
  • Handles 5 V and 3.3 V logic with 115.2 Kbps throughput

Specifications

BrandCoolgear
ModelUS-232TTL33CON
ColorBlack

Questions about this item

How do I install the CoolGear US-232TTL33CON adapter and what is the common mistake?

Plug the DB-9 Female end into your PC's COM port; the DB-9 Male end connects to the TTL/CMOS device. The step people miss is confirming the target device uses 5V or 3.3V logic — the converter tolerates both but mismatched voltage can cause communication errors.

What maintenance or replacement will the CoolGear US-232TTL33CON need later?

The adapter is port-powered with no moving parts, batteries, or firmware, so it requires no scheduled maintenance. Replacement is only needed if the DB-9 connectors suffer physical damage or the internal level-shifting circuitry fails after prolonged use.

What limit appears first when the CoolGear US-232TTL33CON runs under sustained load?

The baud-rate ceiling of 115.2 Kbps is the first hard limit; sustained traffic at that speed is supported, but any attempt to exceed it will cause data loss because the converter's signal-level inversion and port-powered design cannot drive faster transitions reliably.

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