[ntp:questions] Meinberg DCF77 C51 with Linux 2.6

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Sun Feb 11 10:08:55 UTC 2007

>>i started out using an ordinay modem cable but since it did not work at
>>first I started this journey into the RS-232 jungle.
>I would expect that cable to work out of the box.  Unfortunately I can't
>test it, as I don't have a C51.

My tool of choice for this sort of debugging is one of the
RS-232 gizmos with a bunch of LEDs.  You may need a pair of
9-25 pin adapters too, one of each sex/direction.

Plug it in one side and the transmit or receive light should
go on.  Plug it into the other side and the other light should
go on.  You can usually see the blink if any data is being sent.

If both sides light the same LED, you need a null-modem cable
or you need a straight cable when you have a null-modem,
whatever it takes to get the parity right on crossing the RX/TX wires.

You can probably debug it with a voltmeter.  There should be
a real signal on the driving wires - 5 or 10 V.  There might
be a weak signal on the input wires - a volt or 2.

These are my opinions, not necessarily my employer's.  I hate spam.

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