Dear all, I bought myself a Fei FE-5680A with P/N 217400-30352-1, see the picture. I found out that this is a 10MHz version, also has a 1PPS output, lock indicator and a RS-232 interface. My question is about that latter, is it a real RS-232 port, or do I need to add an external MAX232 or MAX3232 to get it going with the proper levels? Could not find a clear answer on the wide web... Best regards, Rob

Hi The reason for not finding a clear answer is unfortunately fairly simple: FEI sold a number of different devices as FE-5680’s. They all got similar part numbers. Next, the design of even specific devices changed at least three times over the “lifetime” of the device. Finally, some of these sell better than others. There is a very real empire of folks who modify the less desirable versions ( no 10 MHz out ….) to add the missing features. Simple answer on any of them: Hook up the power and make sure it at least boots. See if it locks. If not, dive into fixing that problem. Then take a look at the various in’s and outs on your specific device. You might have some luck comparing pictures of the “connector surface” on your device to various other examples. Some of the “rebuilt” parts have connectors in slightly odd locations. Bob > On Jul 25, 2023, at 4:30 PM, Rob040 . via time-nuts <time-nuts@lists.febo.com> wrote: > > Dear all, > > I bought myself a Fei FE-5680A with P/N 217400-30352-1, see the picture. > I found out that this is a 10MHz version, also has a 1PPS output, lock indicator and a RS-232 interface. My question is about that latter, is it a real RS-232 port, or do I need to add an external MAX232 or MAX3232 to get it going with the proper levels? > Could not find a clear answer on the wide web... > > Best regards, Rob > > > <FE-5680A foto.jpg>_______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

You could pop it open to check to double confirm or scope the output for the RS232 levels. I believe all have a Max232 IC near the RS232 serial port. At least mine does. However they made so many revisions it's possible the buyer for a batch never spec'd it as the RS232 was never to be sued, but he board probably has a spot for it. -=Bryan=- ________________________________ From: Rob040 . via time-nuts <time-nuts@lists.febo.com> Sent: July 25, 2023 1:30 PM To: time-nuts@lists.febo.com <time-nuts@lists.febo.com> Cc: Rob040 . <rob040@live.nl> Subject: [time-nuts] Fei FE-5680A RS-232 interface. Dear all, I bought myself a Fei FE-5680A with P/N 217400-30352-1, see the picture. I found out that this is a 10MHz version, also has a 1PPS output, lock indicator and a RS-232 interface. My question is about that latter, is it a real RS-232 port, or do I need to add an external MAX232 or MAX3232 to get it going with the proper levels? Could not find a clear answer on the wide web... Best regards, Rob