WIZnet Developer Forum

TTL or RS-232?

I’m confused about the serial connection to the WIZ145SR. The datasheet indicates RS-232 for the serial architecture but then indicates that serial data port interface is TTL. Wiki indicates that RS-232 uses +3V to +15V for 0 and -3V to -15V for 1. TTL is 0V for 0 and 3.3V or 5V for 1. Can you please clarify if the WIZ145SR uses RS-232 signaling and voltages?


Looking at the schematic for the test board:

Based on the use of level shifters connecting the UARTs to the DB-9s, I’m assuming that the voltages are TTL 0V to 3.3V representing 0 and 1 respectively.

Can you confirm that?

Hello leathmg1,

Sorry for our late response.

Yes, you’re right.
We have wrong information which can make users confused in our datasheet.
UART signal of WIZ140SR and WIZ145SR is TTL, not RS232.
RS232 Transceivers are on the those Evaluation Board.
We’ll fix datasheet with correct information.

Thank you.


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