Multi-Tech Systems MTSGSM - Manual (Page 61)

Appendices
MTSGSM 61
Transparent Mode
In transparent mode, a non error-corrected connection is established between the user and the
remote terminal. Data is then sent asynchronously. Because no error correction is taking place, there
is little delay (latency) in transmitting data over the link.
Non-transparent Mode
In non-transparent mode, a secure error-corrected link is established between the mobile terminal
and the remote modem. The connection between the mobile terminal and the GSM network uses the
Radio Link Protocol (RLP) for error correction. The IWF then establishes a connection to the remote
modem. Apart from having an error corrected link, there are two other main benefits to using non-
transparent mode, these are:
• An increase in data throughput of approximately 20 percent
• Better call handling by the GSM network
Faxing
Sending a fax is similar to sending data. To send a fax, an initial call is made to the network. The call
is then routed through the network to the IWF. The IWF then establishes a connection to the remote
fax machine. The fax protocols are then passed end-to-end between the mobile terminal and the
remote fax machine. Fax data is transmitted synchronously and is not tolerant of any latency;
therefore Transparent mode must be used for Faxing.
GSM Data Benefits
For many years cellular communications have only been associated with voice communications, so
for many, using GSM network for data is a new concept. Many of the benefits derived from using
GSM data are similar to the benefits of using mobile phones. Some of the key benefits are outlined
below:
• Use anytime, anywhere. One major benefit of using GSM data is that you can use it from
any location at any time. There is no need to rely on being able to gain access to a POTS
(Plain Old Telephone Service) line, or wasting time trying to find one. Using GSM provides for
a faster response time for mobile employees. This is becoming an increasingly important
factor in countries where the POTS network is underdeveloped. When used this way, GSM
can provide a real competitive advantage to an organization. For example, sales people out
in the field can send information to relevant parties immediately. This can allow a company to
differentiate itself from its competitors, by its ability to respond to their customers needs in a
time frame that meets (or exceeds) their customers’ requirements.
• Ease of use for international travelers. Using the POTS in a foreign country can often prove
to be a daunting and complex operation. For example, the user needs to select the correct
telephone connector, ensure that the modem is approved for connection to the POTS within
that country, and deal with potential line quality and integrity issues for use over long
distances. All this can be side-stepped by using GSM, where the user is able to use their
equipment in the way they normally would. Using GSM in a foreign country can also prove to
be a more cost-effective solution for mobile data than a fixed network. Typically when staying
in hotels, calls are charged at a premium rate making data communications excessively
expensive. By using GSM users can actually achieve a cost advantage through bypassing
the premium charged by the hotel.
• Secure communications. A company’s information is sensitive and hence it is important that
the integrity of the information is not compromised. Sending data over the POTS network in
its analogue form is not secure. Only a very small number of modems are capable of
encrypting data, and these carry a significant price premium. Because GSM is a digital
technology, it is inherently more secure. As part of the GSM standard, both data and voice