ZyXEL U-336R User Guide - Page 33

Modem Result Codes When you execute or try to execute an AT command, your modem sends a result code to let you know whether the command was executed. An OK result code means the AT command you sent was executed. If you receive an ERROR code, it means the command was invalid. The U-336S/SA also provides result codes that show: • Whether or not a Dial Tone was detected when the modem originated a call. • If a busy signal was detected when the modem originated a call. • If a remote telephone ring was detected when dialing. • The speed, protocol, and error control/data compression method used. • If your modem has detected an incoming ring. Result codes can originate from any of eight result code sets. The ATXn command lets you choose which set of result codes your modem uses. By default, your modem uses result codes equivalent to the ATX5 command. The result code options will be covered more thoroughly in later chapters. Viewing S Register Values Status registers (or "S-registers") contain values that determine the modem's operating characteristics. Whenever you send an AT command to your modem, you are actually changing the value of an Sregister. Basic Modem Operation 19