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8.4.7.5 Future goals
Symbian’s strategy for wireless information devices includes support for Wireless Application
Protocols (WAP), a suite of networking protocols which makes efficient use of both mobile
communications bandwidth and limited display size; Bluetooth, a short-range radio protocol suite
for communicating and synchronising with other wireless information devices and with PCs; and
continued messaging, browsing, Internet and security enhancements.
8.4.8. Components
Communications Components, and their main relationships
The major EPOC communication components are shown above. We will examine each in turn.
8.4.8.1 Client-Server architecture
At the heart of EPOC’s communications are its servers — the serial comms server, the telephony
server and the sockets server — together with the comms database.
Accessing system facilities via servers instead of using them directly means that they may be
shared by multiple clients. This is a highly significant architectural advantage. The use of servers
also encourages a high degree of functional abstraction; this means that clients can rely on being
able to use the same API without needing to know the exact hardware device or software protocol
which might be used to provide the service required.
8.4.8.2 Serial comms server
The serial comms server provides a serial port API to clients. It also specifies a provider interface
which allows any serial-like protocol to appear as a port. EPOC uses this to access both real serial
communications over an RS232 line and also IrCOMM over an infrared device.
8.4.8.3 Telephony server
The telephony server provides a standard API which enables its clients to initiate, control and
terminate data, fax and voice calls using the same methods for any hardware. EPOC provides, as
standard, generic modules for GSM mobile phones and also for terrestrial modems using AT
command sets. The architecture makes the task of adding support for devices implementing
different protocols quite straightforward.
8.4.8.4 Sockets server
The sockets server provides a BSD-like sockets API to clients. It also specifies a provider interface
which allows sockets to be implemented using a variety of protocols. EPOC provides Internet and