Operation Manual

131
Appendix A: Technical Information on GSM Operation
English
end. For this reason, not all ISDN devices are compatible
with data connections from GSM.
You may connect to V.110 terminal adapters, V.110 BBS
ports and to CompuServe’s ISDN dial-in ports. The
following diagram shows the Mobile ISDN protocol stack
for connections to V.110 devices:
Fig. 9 Mobile ISDN Stack, V.110
FRITZ!com for example can be configured to V.110 at
9600 bit/s by selecting the appropriate B-channel setup.
This setup allows you to dial in to V.110 BBSs over Mobile
ISDN.
Most ISDN applications (such as Euro-file transfer or
Internet access) support the synchronous protocols
X.75 or HDLC transparent, however. These can be used
with the AVM ISDN-Controller B1 or an AVM
FRITZ!Card at the remote end (using the new FRITZ!Card
driver found on the CD-ROM; see also Section 4.2). The
Mobile ISDN protocol allows you to establish the end-to-
end synchronous digital connections characteristic of
ISDN between GSM and ISDN terminals. Figures 10 and
11 show the Mobile ISDN stack at the local and remote
ends of the connection, for X.75 and HDLC transparent,
respectively:
FRITZ!com
(async. V.110)
CAPI 2.0
B1=2 (V.110)
B2=1 (Transparent)
B3=0 (Transparent)
L2R
RLP
Bfa
L2R
Air Transmission
RLP
S
0
ISDN Line
S
0
V.110
Mobile Station with AVM
Mobile ISDN-Controller M2
and V.110 Application
ISDN V.110 Station
Mobile Switching Center
(MSC)
V.110
CAPI Port
Custom Config
AT S31=2; S51=0
CompuServe
WinCim
Terminal
Adapter
CompuServe