#Arduino Ethernet Board telnet protocol
A=pin0 B=pin1 C=...
Syntax: "#[<>~|]{1}[A-Z]{1}\n"
Examples of Commands:
"#>C1\n" set pin 2 to out mode and set it to high
"#<E\n" set pin 4 as input and read digital value
"#~A\n" read analog input 0 and return value
"#|mymessage\n" sends to serial TX message