Fingerprint Sensor AS608 - A Beginner's Guide
One touch can replace keys. This project uses an optical fingerprint sensor to enroll users and then grant access with a quick scan.
read tutorial →
INTRODUCTION
This converter uses MAX202-based level shifter for converting TTL (Transistor-Transistor Logic) -level serial to standard RS232 serial.
RS232 is widely used in radio modifications,phone flash, XBOX360 flash, GPS, vehicle detection, DVD flash, hard disk repair set-top box upgrade. It can be used to program STC MCU, NXP MCU,Renesas MCU, STM32 MCU, N+-2EC MCU.
This converter can be connected to an Arduino Serial pin (0,1) to convert standard Arduino ttl to RS232. It allows arduino talk to hundreds of RS232 devices.
RS232 DB9 Pinout Diagram
RS-232 Maximum Cable Length
The maximum cable length for RS-232 is 50ft, but in practise depends on baud rate, cable specific capacitance and ambient noise. The table below contains some rules-of-thumb from experiments done by Texas Instruments years ago.
| Baud rate | Maximum range / cable length |
|---|---|
| 19200 | 50ft |
| 9600 | 500ft |
| 4800 | 1000ft |
"In telecommunications, RS-232 is a standard for serial communication transmission of data. It formally defines the signals connecting between a DTE (data terminal equipment) such as a computer terminal, and a DCE (data circuit-terminating equipment or data communication equipment), such as a modem. The RS-232 standard is commonly used in computer serial ports. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997." From Wikipedia
SPECIFICATION
- 4 pin connector - GND, Logic out (STX), +5v, Logic In (SRX)
- Suitable for use with most microcontrollers
- 300 to 115200 bauds
- Pre-assembled board
- DB9 Female Connector (RS-232)
- Standard Header Connector (TTL)
DOCUMENTS
SHIPPING LIST
- RS232-TTL Converter x1
Manila stock. Order before 16:00 PHT, ships today via J&T or LBC. Provincial: 1–3 working days.
Schools / class POs: we accept Purchase Orders for accredited schools and universities. contact us with your PO details.
Returns: 7-day inspection window for DOA units. Email proof of issue and we ship a replacement.
Customers also bought
Build with this board
Thumb Joystick - A Beginner's Guide
Wire a joystick to your Arduino, read X/Y, then print UP / DOWN / LEFT / RIGHT to the serial monitor.
read tutorial →Motor Drive (BTS7960 43A) - A Beginner's Guide
Bench-test a 43 A motor driver before wiring the full project. Catches weak power, mis-pinning, and dead boards before they cost you time.
read tutorial →Raspberry Pi Pico (RP2040) - A Beginner's Guide
Coming from UNO and the Pico won't show a COM port? Here's the BOOTSEL trick, the driver fix, and the first sketch that actually works.
read tutorial →Notes from the bench
Ask the community
Project Showcase — show what you built
Share what you built. Photos, BOM, what worked, what didn't.
view thread →How to ask a good question (and actually get answers)
Symptom + what you tried + clear photo = answers within hours.
view thread →ESP32 brownout when wiring a sensor — fixes that worked
Brownout reset when adding a sensor? Notes on supply decoupling and GPIO checks.
view thread →First Arduino — sketch upload error, what to try?
Upload failing on your first Uno? Driver, COM port, board match — checklist inside.
view thread →