Filter
Top Products
SETTING UP DIAL-IN SYSTEM 16 (16)
Mobile Phones
3.1 21.04.99
Copyright©Nokia Mobile Phones 1999
• Switch type: Euro-ISDN
• Mode: Asynchronous
With these settings in the Shiva terminal server end, and AT+CBST=71 in the communicator’s modem
initialisation, the ISDN connection with Shiva works.
5. KNOWN PROBLEMS
This section presents the settings needed to solve some known connectivity problems. In some cases, it is
necessary to explain the situation further so that the problem case can be solved.
5.1. ISDN Connections
ISDN dial-in lines can create interesting problems. In most cases, when the dial-in system has been configured,
the only thing left to do is to set the communicator as a null modem. Thus the ISDN modem does not care about
the speed of the communicator. To set up the communicator as a null modem:
In the Internet application, choose Settings à choose Internet access à highlight the Internet
access point and press Edit à choose Advanced settings à and type “AT+CBST=71” into the
Modem initialisation field.
Note: The GSM network operator must support ISDN data calls.
5.2. Shiva Terminal Servers
The communicator supports PAP and CHAP protocols in PPP connection authentication. Shiva has its own
authentication protocol called SPAP that the communicator does not support. When using a Shiva terminal server
with the communicator, some configuration settings must be changed. Since SPAP cannot be used, a TACACS
server should be set-up and configured to the Shiva (extended TACACS is recommended). In the communicator,
the compression option must be off. The configurations are explained in more detail in section 3.
5.3. PPP Data Calls Over Long Distances
If some of the dial-up connections to the PPP service are made over exceptionally long delay links, if the PPP
server uses the default 3-second restart timer, the service provider’s PPP protocol state machine may be unable
to converge the option negotiations.
An example of a long delay link is a GSM data call from Hong Kong to Helsinki, Finland. The Radio Link Protocol
(RLP) of GSM that is used to provide reliable asynchronous data service over the wireless link adds more delay to
the satellite link delays. This problem can be avoided by configuring the PPP server to use a greater restart timer
value (e.g. 11 seconds) or to configure the PPP server to use some dynamic scheme for updating the restart timer
value if the server is capable of doing so.