• 8 LEDs are connected to the RD port. When the J3 is plugged in, the LED is enabled. J3 is unplugged and the RD port is completely released.
• External 5V DC power interface (send USB power cable without additional purchase).
• Standard RS232 communication interface, microcontroller board and computer communication interface.
• The 4-bit independent keyboard is connected to RB0 RB1 RB2 RB3.
• Onboard 4M crystal oscillator, the socket crystal frequency can be replaced at any time.