Data Hacking

152 Part II — Software Hacks
A USB port can support data transfer at 12 Mbps (megabits per second), whereas serial ports
can manage only 115.2 Kbps (kilobits per second). Another advantage of USB over the serial
port is that it breaks the “one port, one device” rule that was pretty much absolute with a serial
port. A USB port can support up to 127 devices daisy-chained to a single port.
While the USB port has gained a lot of popularity and most computers sold today have two,
if not four, ports per machine, GPS manufacturers haven’t been as speedy in jumping on the
bandwagon. Some manufacturers (such as Garmin) make USB cables for some, but not all, of
their handheld units.
Bluetooth
Wires are fine for connecting devices together, but they lack cool. For the ultimate in cool and
convenience, what you need is a wireless connection. Bluetooth is a great way to achieve this.
Bluetooth is a wireless communication technology that can be found on many PCs, PDAs, and
cell phones. It offers many advantages over a standard wired connection:
Greater distance: You can place the GPS device farther from your PC than you can
with a standard wired connection (most COM cables are under a meter long).
Less tangle: Cables nearly always mean tangles. Wireless connections eliminate cables
and thus eliminate tangles.
Reduce the risk of damage: Tangled cables can place stress on connectors that can damage
the cable or the device. Wireless eliminates this problem.
Send the signal through walls: If you have a GPS on a boat, for example, you might
have the GPS outside and the PC inside. A wireless connection eliminates the need for
holes in the wall for cables. It also makes it easier to move your GPS and PC without
having to reroute cables.
Easier to connect: If connections mean cables, you can find yourself needing different
cables for different GPS units and PCs/handheld devices. A wireless connection eliminates
this, making the process of setting up connections easier.
The only problem with wireless connections is that you need a GPS that is specifically
designed for Bluetooth — it’s not something you can bolt onto any GPS. GPS Bluetooth
units are normally a receiver only. Figure 7-6 shows a Haicom Compact Flash GPS along
with a Bluetooth “slipper” that it can be attached to, enabling the data to be transmitted to
any Bluetooth receiver.
Once you have a Bluetooth device, you need a Bluetooth receiver. These are available in a variety
of styles. Some devices, such as the HP iPAQ 5545 (shown in Figure 7-7), already have
built-in support for Bluetooth.
PCs that don’t have support for Bluetooth can have support added with a USB Bluetooth
dongle, such as the one shown in Figure 7-8.
These dongles plug into a spare USB port. You install the drivers and there you have it —
Bluetooth support on pretty much any PC.