Farallon Communications 612 - Manual (Page 112)

A-2 Netopia ISDN Modem User’s Guide
Modem basics
A modem provides computer-to-computer communications over
telephone lines. It acts like a telephone by dialing and answering
calls. Your Netopia ISDN Modem uses digital technology to connect
to the public telephone network. Yet, like analog modems, you use
standard AT commands to communicate with the ISDN modem.
Operating modes
Command mode allows the Netopia ISDN Modem to accept
operating commands and configuration settings from the keyboard.
The ISDN modem enters command mode when:
■ Power is applied (hardware reset)
■ No carrier is detected
■ The ISDN modem's carrier is lost
■ The escape sequence (+++) is issued
In online mode, the Netopia ISDN Modem is “on-line” and sends any
data it receives from your computer out to the remote ISDN device.
The ISDN modem attempts to go into online mode when:
■ The AT dial command ATD is issued for originating a call
■ The AT answer command ATA is issued for answering a call
The escape sequence (+++) allows you to switch from online mode
to command mode without breaking an established connection with
a remote ISDN device. The ATO command returns the ISDN modem
to online mode.