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Date:      Wed, 8 May 2002 21:52:37 +0400
From:      "AMI" <ami@lycos.ru>
To:        <freebsd-questions@FreeBSD.ORG>
Subject:   Re: COM port for voltage command/measurement ?
Message-ID:  <032501c1f6c8$34094780$0100a8c0@p7>
References:  <3CD93DC7.6C037CA7@is-production.com>

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Hello!

I think you may use DTR as command for external relay about +12-3 V. But
don't use RTS because it's info wey and haven't true voltage for.

It is cheme of the connector:

9 PIN D-SUB MALE at the Computer.

Pin Name Dir Description
1 CD <== Carrier Detect
2 RXD <== Receive Data
3 TXD ==> Transmit Data
4 DTR ==> Data Terminal Ready
5 GND === System Ground
6 DSR <== Data Set Ready
7 RTS ==> Request to Send
8 CTS <== Clear to Send
9 RI <== Ring Indicator

Note: Direction is DTE (Computer) relative DCE (Modem).

Andrew


> Hi,
>
> I did some search on your archives and others, and found no info on that
> :
>
> I need to use a com port to command voltage on com port pins, to be able
> to drive external relays.
>
> Would anybody have any hint/example for that function ?
>
> Best regards,
> --
>
>  __________ Bernard DUGAS ________________________________________



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