Compaq W25 - Manual (Page 3)

1 Introduction
This document gives a brief description of the Fax over IP and the
implementation in the Ericsson W25. It also includes a guidance of how to
configure the Ericsson W25.
1.1 Background
The Ericsson W25 is intended for residential and SOHO applications. The
focus for the Ericsson W25 is to enable both broadband data and voice
calls using existing 3G network. Additionally support for analog Fax
operation is essential when targeting business users such as SOHO users.
Fax support in GSM mobile networks is standardized, but not in 3G mobile
networks. The available options in 3G mobile networks are T.37, store and
forward mailbox, or T.38 Fax over IP. Since Fax communication is
considered legally binding when doing business, the demand on Fax
operation is that the sender of a Fax can get a receipt that the fax has been
delivered to the recipient in real-time. Therefore, Ericsson has chosen Fax
over IP (T.38) using packet switched connection in the Ericsson W25 to
enable Fax operation in 3G mobile networks. This, since it is the only option
that can guarantee that a fax has been delivered to the recipient in real-
time. This can be done thanks to HS(D)PA introduced in 3G mobile
networks with features such as increased data bandwidth and reduced
delay.
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