Specifications

33
Figure 2.4.5-1: USB male Type A connectors. Reproduced with permission from
sparkfun.com.
This arrangement would utilize all four pins. Although the physical arrangement
of the pin matrix is different in a Type B USB connector, the actual function of the
pins has not changed. As such, it will still be compatible. In addition, if a cable is
still desired, it can still be used, although a female Type A to male Type A cable
will have to be utilized, rather than the Type A to Type B cable.
2.4.6 Wireless
Another option would be to eliminate the wired connection altogether, and go
with a wireless standard. This would greatly simplify operation of the portable unit
and the base unit, as well as create fewer parts.
There are many options for implementing wireless into the portable and base
units. The simplest method would be to use some sort of method integrated with
a major part of the board and portable unit circuitry. The microcontroller would
most likely be the most likely part to be investigated for having integrated
wireless communications, if possible. Most notably, this will be the most compact
solution. This will be discussed in more detail in section 2.1. Power will still need
to be a consideration just for charging the battery, and will most likely use a
simple barrel jack interface.
2.4.7 Power & I/O Interface Comparison
Several options have been discussed. While each have their own advantages
and disadvantages, wireless would be the most ideal. Depending on which
protocol is utilized, it may also offer an additional layer of security by not allowing
the user to use a widely available standard to interface and compromise the
integrity of the device. The results of the comparison are summarized in Table
2.4.7-1.