Technical information

W24 RAS Server
2-82 AT+i Commands Reference Manual May 31, 2008
W24 RAS Server
Introduction
W24 features an internal Remote Access Server (RAS) that allows a remote dialer to dial into
W24 using an active modem platform. When configured as RAS, W24 answers the incoming call
and negotiates a PPP connection.
W24's RAS supports acknowledging an IP address request from the remote dialer side, as well as
assigning a default IP address. Once the connection is established, the client can browse W24's
website. (If the AWS parameter is set to a non-zero value.) All other W24 IP protocol
functionality is also enabled, allowing the host to issue Internet protocol AT+i commands based
on the PPP connection. Note, however, that since W24 is not connected to an actual ISP in this
mode, W24 does not have access to the public Internet and thus only direct connections between
W24 and the connected PPP client are possible.
RAS Parameters
Three parameters govern the use of W24's RAS server:
RAS Theory of Operation
When a remote client dials into W24, the modem RING strings are transferred by W24 (which
defaults to transparent mode) to the host. When the RAS feature is enabled (RAU contains a
value), W24 picks up the line and negotiates a PPP connection by issuing the ATA (modem)
command after RAR RING strings have been received.
If the host chooses to manage a direct (modem-to-modem) data connection, it can pick up the line
before RAR RING strings have arrived by issuing the ATA modem command.
RAU RAS Login User Name.
The RAU parameter defines the allowable user name for
login purposes when W24 answers an incoming call as a
RAS. The remote dialer must specify the correct user name
and matching password in order to successfully complete the
PPP connection. This parameter must have a non-empty
value for the RAS feature to be enabled. Otherwise, when
RAU is empty, W24's RAS is effectively disabled. When
RAU contains the special character (*), RAS is enabled but
no authentication is required.
RAP RAS Login Password.
The remote dialer must provide the correct password in order
to successfully complete the PPP connection. When the RAP
parameter is empty or contains a (*), any password string is
accepted, in effect nullifying the authentication process.
RAR Number of RINGs before picking up the line.
When the RAS feature is enabled, the RAR parameter
defines the number of RINGs that must arrive before W24
picks up the line and transfers control to its RAS.