Operation Manual

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Appendix A: Technical Information on GSM Operation
Both FRITZ!com, the terminal module of the software
suite FRITZ! included with the Mobile ISDN-Controller
M2, and the AVM ISDN CAPI Port Driver support this
mode.
Fig. 8 Protocol layer model for communication with
analog modems
A.2.2 Group 3 Fax Devices
Group 3 fax software for CAPI 2.0 can be used with the
Mobile ISDN-Controller M2 to connect to any Group 3
fax device.
A.2.3 ISDN Equipment
The Mobile ISDN-Controller M2 supports telefax and
data connections to ISDN lines. Purely digital gateways
(UDI = Unrestricted Digital Information) between GSM
and ISDN make this possible. These services are not yet
provided by all GSM operators in all countries.
In order to compensate for the difference in bandwidth
(GSM: 9600 bit/s; ISDN: 64000 bit/s), the asynchronous
bit rate adaptation protocol V.110 is used at the ISDN
FRITZ!
com
CAPI 2.0
B1=8 (Asynchronous Analog Modem)
B2=1 (Transparent)
B3=0 (Transparent)
L2R
RLP
Bfa
L2R
Air Transmission
RLP
a/b
PSTN Line
a/b
V.32
Modem
Application
Mobile Station with AVM
Mobile ISDN-Controller M2
Analog Station
Mobile Switching Center
(MSC)
V.32
Dial-Up
Networking
CAPI Port
V.32bis
RS 232
T-Online-
Decoder