How a services router initializes usb modems – Juniper Networks J-Series User Manual

Page 53

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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.

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

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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:

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As a backup interface and a dialer filter

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As a backup interface and dialer watch interface

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As a dialer watch interface and a dialer filter

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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-string

command

to the initialization commands on the modem. For more information about configuring
modem commands for the

init-command-string

command, see “Modifying USB Modem

Initialization Commands” on page 41.

If you do not configure modem AT commands for the

init-command-string

command,

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

Description

Modem Command

Attention. Informs the modem that a command follows.

Instructs the modem to wait 45 seconds for a telecommunications service provider
(carrier) signal before terminating the call.

S7=45

Disables the auto answer feature, whereby the modem automatically answers calls.

S0=0

Displays result codes as words.

Disables reset of the modem when it loses the carrier signal.

&C1

Disables the display on the local terminal of commands issued to the modem from
the local terminal.

Enables the display of result codes.

Enables Microcom Networking Protocol (MNP) error control mode.

&Q8

USB Modem Overview

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Chapter 2: Setting Up USB Modems for Remote Management