More information about the Dial : http://voip-info.org/wiki-Asterisk+cmd+dial<br>30 :  The timeout parameter is optional. If not specifed, the Dial command will wait indefinitely, exiting only when the originating channel hangs up, or all the dialed channels return a busy or error condition. Otherwise it specifies a maximum time, in seconds, that the Dial command is to wait for a channel to answer.<br>H: Allow the caller to hang up by dialing * <br>r: Generate a ringing tone for the calling party<br>R: Indicate ringing to the calling party when the called party indicates ringing, pass no audio until answered.<br>g: When the called party hangs up, exit to execute more commands in the current context. (new in 1.4)<br>i: Asterisk will ignore any forwarding (302 Redirect) requests received. Essential for DID usage to prevent fraud. (new in 1.4)<br>m: Provide Music on Hold to the calling party until the called channel answers.<br>L(x[:y][:z]): Limit the call to 'x' ms, warning when 'y' ms are left, repeated every 'z' ms)<br>%timeout% tag is replaced by the calculated timeout according the credit & destination rate!.