Tag Archives: Data Communication

Bandpass Filter for Bell103A Originator Modem

Posted on March 3, 2011 by Rend

Bell103A modem standard specify that the originator (the caller) uses 1070Hz and 1270Hz frequency shift keying for transmission, and listen for 2025/2225Hz FSK transmitted by the answering modem. This bandpass circuit filter out any frequency beyond 2025-2250 Hz to improve … Continue reading →

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RS232 Line To 5 V Level Converter

Posted on January 5, 2011 by Rust

RS 232 line to 5 V converter circuit schematic diagram is shown on the following figure. The MAX680 is normally used as a charge pump voltage converter. This converter can convert +5 V to ±10V. The MAX 680 works in … Continue reading →

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LTC1045 TTL RS-232 Converter

Posted on December 21, 2010 by Rust

A simple way to build a battery-powered RS-232 receiver  circuit is shown on the following schematic diagram. This circuit convert RS232 level to TTL level. Because the 100 KΩ resistor prevents device damage, the input voltage can be driven as much … Continue reading →

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