provide Ethernet devices - dry contact snmp or email, rs-232 serial, buffer, rs232 rs485 rs422...Go

Simple hardware expands PC's COM port from COM1 to COM1/1 and COM1/2. No active parts....Go

Excellent RS232 utorial and data sheet....Go

The developer's resource for computer interfacing, especially Ethernet and Internet communications for embedded systems, USB, parallel port, and RS-232 and RS-485 serial communications. Plus info about 8052-Basic microcontrollers and making printed-circuit boards....Go

an RS232 Serial Interface to Controller Area Network (CAN) adapter. Powered by the MicroChip PIC16F876.The I2C232 RS232 to I2C adapter from Emicros provides a powerful, low-cost solution to interface to an I2C bus...Go

There're many, who built the Easy Programmer or C-52 Evaluation Board, asking for the RS232C level converter chip, DS275. Many have changed to MAX232 instead, because of not available in his home. Here is another simple and cheap circuit using small signal transistor providing TTL to RS232C level converter....Go

A standard serial interfacing for PC, RS232C, requires negative logic, i.e., logic '1' is -3V to -12V and logic '0' is +3V to +12V. To convert a TTL logic, say, TxD and RxD pins of the uC chips, thus need a converter chip. A MAX232 chip has long been using in many uC boards. It provides 2-channel RS232C port and requires external 10uF capacitors. Carefully check the polarity of capacitor when soldering the board. A DS275, however, no need external capacitor and smaller. Either circuit can be used without any problem...Go

This self powered interface circuit electrically isolates the TxD and RxD lines from the PC serial port and protect the PC from direct connection to hazardous voltages....Go

This interface circuit provides electrically isolated RS485 communication inteface to the PC serial port the isolation circuit protect the PC from direct connection to hazardous voltages....Go

This interface circuit provides electrically isolated RS422 communication interface to the PC serial port the isolation circuit protect the PC from direct connection to hazardous voltages....Go

Connect serial transmit bit of the transformerless supply PIC16F84 circuit with COM1 through the use of isolation device. Protect your notebook from direct connected to power line....Go

Connecting PIC16F84 to internet gateway, set/clear bit, read bit from wherever internet terminal available. Free download Easy-Server V0.9 beta!...Go