TRS3122EEVM: RS232 EVM

jose ramon foronda melo

Part Number: TRS3122EEVM

Hi, guys I'm exploring some Integrated Circuit to use it in an RS232 application, so I found that there exists this Evaluation Kit TRS3122EEVM , and I'd like to understand the connections in the schematic.

Specifically, in Fig.1. I show the schematic that is showed in pg7 of TRS3122EEVM , and J1 represents the DB9 connector for stablish an RS232 communication. My doubt is: pin 2 (RX pin as per the standard) in J1 is connected to Dout1, but this Dout1 is an output from the U1, and there it is my confussion. So, as long as I understand if a pin is for RX operation, I understand it is used to receive data (so in one device I transmit with TX and at the other device I receive with RX), so in this case RX1 should be connected to a receiver pin of U1 instead of a driver pin of U1. Can someone please explain this to me? what am I missing here?

Thanks

Fig.1. RS232 EVM

over 5 years ago

0 jose ramon foronda melo over 5 years ago

Prodigy 230 points

Fig.1. RS232 EVM

0 Miguel Robertson over 5 years ago in reply to jose ramon foronda melo

TI__Guru 62920 points

Hi Jose,

This pinout is intended to match what would be used on a "DCE" side of a cable (like a modem device) rather than the "DTE" side (for example, a PC). That's why a female connector is used rather than a male connector like you would see on a PC. The transceiver connections are different on each side since each DOUT port would need to connect to a DIN on the other side and vice-versa. Let me know if that doesn't make sense.

Regards,
Max

0 jose ramon foronda melo over 5 years ago in reply to Miguel Robertson

Prodigy 230 points

Hi Max, thank you for your message. I was confussed because I had not realize that those DCE and DTE have an specific pinout direction, thank you for your help.

additionally, I consulted this TI-DESIGN, which help me understand the direction of each DCE and DTE interface.

Thank you

Jose

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TRS3122EEVM: RS232 EVM