Juniper Networks J-Series manual How a Services Router Initializes USB Modems, S0=0

Chapter 2: Setting Up USB Modems for Remote Management

■The dialer interface must be configured to use PPP encapsulation. You cannot configure Cisco High-Level Data Link Control (HDLC) or Multilink PPP (MLPPP) encapsulation on dialer interfaces.

■The dialer interface cannot be configured as a constituent link in a multilink bundle.

■If you are using the same dialer interface for ISDN connections and USB modem connections, the dialer interface cannot be configured simultaneously in the following modes:

■As a backup interface and a dialer filter

■As a backup interface and dialer watch interface

■As a dialer watch interface and a dialer filter

■As a backup interface for more than one primary interface

How a Services Router Initializes USB Modems

When you connect the USB modem to the USB port on the Services Router, the router applies the modem AT commands configured in the init-command-stringcommand to the initialization commands on the modem. For more information about configuring modem commands for the init-command-stringcommand, see “Modifying USB Modem Initialization Commands” on page 41.

If you do not configure modem AT commands for the init-command-stringcommand, the router applies the following default sequence of initialization commands to the modem: AT S7=45 S0=0 V1 X4 &C1 E0 Q0 &Q8 %C0. Table 23 on page 31 describes the commands. For more information about these commands, see the documentation for your modem.

Table 23: J-series Default Modem Initialization Commands

Modem Command	Description
AT	Attention. Informs the modem that a command follows.
S7=45	Instructs the modem to wait 45 seconds for a telecommunications service provider
	(carrier) signal before terminating the call.
S0=0	Disables the auto answer feature, whereby the modem automatically answers calls.
V1	Displays result codes as words.
&C1	Disables reset of the modem when it loses the carrier signal.
E0	Disables the display on the local terminal of commands issued to the modem from
	the local terminal.
Q0	Enables the display of result codes.
&Q8	Enables Microcom Networking Protocol (MNP) error control mode.

USB Modem Overview ■ 31