User guide

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The SIR/FIR layer is purely hardware. The SIR (Serial IR) layer supports speeds up to
115k bps while the FIR (Fast IR) layer supports speeds up to 4M bps. IrLAP is the IR
Link Access Protocol that provides a data pipe between IrDA devices. IrLMP, the IR
Link Management Protocol, manages multiple sessions using the IrLAP. Tiny TP is a
lightweight transfer protocol on which some higher-level IrDA layers are built.
IrComm provides serial and parallel port emulation over an IR link. IrLAN provides an
access point to Local Area Network protocol adapters.
OBEX is an object exchange protocol that can be used (for instance) to transfer business
cards, calendar entries or other objects between devices.
The Palm OS implements all the required protocol layers (SIR, IrLAP, IrLMP, and Tiny
TP), as well as the OBEX layer. Palm III devices provide SIR (Serial IR) hardware
supporting the following speeds: 2400, 9600, 19200, 38400, 57600, and 115200 bps. The
stack is capable of connection-based or connectionless sessions.
From the IrDA layers Palm provides, we use only the lower level, SIR level. In PalmOS,
the SIR level of IrDA can be accessed through the New Serial Manager, which is capable
of managing multiple serial connections within a Palm device.
The main difference between the new serial manager and previous versions is that the
new serial manager supports multiple physical serial hardware devices and virtual serial
devices, the detailed operation of which is abstracted from the main serial management
code.
The new serial manager manages multiple serial devices with minimal duplication of
hardware drivers and data structures. In older Palm systems, the serial library managed
any and all connections to the serial hardware in the 68328 (Dragonball) processor, which
was the only serial device in the system. Newer systems contain additional serial devices,
such as an IR port.
The figure below shows the layering of communication software with the new serial
manager and hardware drivers: