AR1688 Software Development Guide   Software API overview, license. SDCC compiler test, 3.0.0, 2.9.0. Other tools used in sdcc\bin (2). Quick start: Try the first change. In sdcc\src directory, use command line like mk gp1266 sip us to compile. Understand relationship between upgrade file name and command line parameters. Use TFTP to upgrade the compiled file. Any thing wrong? Try safe mode recovery (2). Understand Z80 (2) (3). Regional and language options. Font: ISO 8859, 2x16 Character LCD, upgrade, resources, detail steps. Ethernet chips: old faithful RTL8019AS (2) (3), do NOT use DM9003, KSZ8842 may be a good try. How to change MAC address. Use IVR. Use GPIO. SIP protocol: use MESSAGE for short message display, User-Agent content, Disable STUN with Asterisk. UART and VoIP module: High Level UI Protocols, 8051 example, AVR mega 128L example, test VoIP module functions with AR168G/GP1266/GP2266 IP phones. List of #define. List of .h files. List of .c files. List of functions. List by software version. Debug problems, use syslog debug messages.