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	Mon, 22 Sep 1997 08:50:26 +0930 (CST)
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Date: Mon, 22 Sep 1997 08:50:26 +0930
From: Greg Lehey <grog@lemis.com>
To: Jonathan Chen <jonc@pinnacle.co.nz>
Cc: FreeBSD Questions <questions@FreeBSD.org>
Subject: Re: Serial Port
References: <199709191750.KAA00710@celebris.tddhome> <Pine.SGI.3.96.970922091901.16205C-100000@tui.pinnacle.co.nz>
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In-Reply-To: <Pine.SGI.3.96.970922091901.16205C-100000@tui.pinnacle.co.nz>; from Jonathan Chen on Mon, Sep 22, 1997 at 09:22:40AM +1200
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On Mon, Sep 22, 1997 at 09:22:40AM +1200, Jonathan Chen wrote:
> On Fri, 19 Sep 1997, Thomas Dean wrote:
>
>> I am attempting to use a serial port to talk to a Gramin GPS 45XL.
>>
>> I can talk to the device, read and write data.  The results make
>> sense.
>>
>> I am using /dev/cuaa0.
>>
>> I have one problem.  The communications with the device are not
>> reliable.  I execute an application to send the device a command and
>> read the results.  It works.  I issue the same command again and it
>> hangs.  Actually, I use select() and it times out after 15 seconds.
>> Increasing the timeout to 100 seconds does not change things.
>
> How about enabling h/w flow-control with the tcsetattr() call? If I
> remember correctly the flags you use are CCTS_OFLOW and CRTS_IFLOW
> (check out the man entry).

Unfortunately, the serial interface has only Ground, TxD and RxD.  It
would be interesting to see if it understands XON/XOFF, though.

Greg