Problem
Hi NavMicroSystems
My aim is to send SMS using a Nokia 7250i phone using a PIC microcontroller most probably 16F877A, since
it has hardware USART
I went through entire thread from page 1 to 2. The problems I faced can be listed as follows
1) I am a beginner so the schematic Stu746 told, had me in some dilema
I thought only modifications to be done are to omit the PC part with two MAx232 ICs
2) I have a Nokia 7250i : which has an embedded modem as I learnt from Nokia website - Solved
But I have a DAU 9P-FBSU cable which I use to connect my phone with other third party
softwares and it is successful. But using Hyperterminal it is not responing to any AT commands. Do I
need an DLR 3P cable. How can I do it with my DAU 9P FBUS cable...?
3) To my knowledge phone voltages are between 3.6 and 5V so why we need a MAX232 IC to connect
the phone to a PIC. We may need it in case we are connecting it to PC COM port. where voltages are
between +15 and -15V. This contradicted with the NavMicrosystems post on 24th February 2004, 22:05
Unless of course you are using the phone datacable inbetween !.
For your reference I have attached the circuit I built.
regards
aruran
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