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the Ericsson T10s. This phone is particularly of interest because its port gives a direct
TTL level output that can be interfaced to a serial port on any microcontroller. We don’t
need an extra IC MAX232 for level conversion. This reduces the size of the whole
system.
Figure 3.2 Ericsson T10s Pin-Out
This also has the same problem like the F-Bus jacks in the Nokia phones; a serial cable
will need to be made by cutting either a charger or headset cord. Another drawback is
that this phone is old and not in the market.
3.4 Motorola C168i
Motorola C168i has small size and serial communication capability makes it an
ideal candidate for use with this project. The features of phone will be discussed in
sufficient detail in the following pages. Though the phone is simple and has minimum
features it is available with an AT&T prepaid SIM card that can be activated for a
data/calling plan according to the user’s needs. Cost-wise, the phone is expensive as each
SMS message costs about 20 cents. For our design, since it is user-interactive, the
phone’s data plan to be chosen depends on how often the user sends the data to the