6.1 Dialer Rotary
6.1.2 Configuring the interface dialer
In the previous chapter, you saw how to configure call parameters under a physical interface. The following are some commands required for setting up rotary groups.

The command dialer string is used to specify the phone number to dial when placing a call from an interface to a specific destination. A modem chat-script must be defined and used to implement dialing on asynchronous interfaces. The syntax is as follows:

Router(config-if)#dialer string dial-string

dialer string and dialer group Commands
If a dialer string command is specified without a dialer group command with access lists defined, dialing is never initiated. If the debug dialer command is enabled, an error message displays and indicates that dialing never will occur.

By default, packets are dropped during the time required to establish a connection. To prevent this, use the dialer hold-queue command, which allows interesting outgoing packets to be held in a queue while dialing takes place. The number of packets allowed in a queue ranges from 0 to 100. The syntax is as follows:

Router(config-if)#dialer hold-queue number