Handheld Synchronization

Without the capability to transfer and synchronize data back to a desktop system, there’s little benefit in having a word processor or similar feature on a PDA – particularly as relatively few devices support printing via a parallel printer port. Its no surpass then that this is a feature that has improved significantly in recent years, not least thanks to the efforts of third-parties who’ve developed both hardware accessories for use with PDA docking cradles and software applications designed to make the synchronization task as comprehensive and as simple to execute as possible.

Most PDAs employ a similar docking design which enables the device to be slotted into a small cradle connected to the desktop PC via a serial cable. As well as facilitating connection to the desktop device, many cradles also provide a source of power, recharging the PDA’s battery whilst the device is docked. However, two wireless technologies – one with us now (IrDA), the other due to become available in the near future (Bluetooth) – are likely to play an increasing role in the synchronization task in the future.

Since its formation in June 1993 the Infrared Data Association (IrDA) has been working to establish an open standard for short range infrared data communications. The IrDA chose to base its initial standards on a 115 Kbit/s UART-based physical layer that had been developed by Hewlett-Packard, and an HDLC based Link Access Protocol (IrLAP) originally proposed by IBM. It is a point-to-point, narrow angle (30° cone) data transmission standard designed to operate over distances up to 1 metre at speeds between 9.6 Kbit/s and 16 Mbit/s.

In the mobile computing arena IrDA is commonly used for establishing a connection between a portable computer and a mobile phone for establishing a dial-up connection to the Internet. IrDA also specifies the IrLAN protocol for connecting an IrDA-enabled device to a wired network.

Although it achieved a worldwide installed base of more than 50 million units, many consider IrDA to have been a failure. The manner in which many manufacturers implemented the standard resulted in numerous incompatible flavours of IrDA. In addition, software support was poor. The result was that IrDA is difficult to use and has never worked as well as it was supposed to – which is why so many are hoping that the Bluetooth initiative, started in mid-1998, will fare better.