[Rxtx] loopback puzzle

[Dr. Stephen Judd]

I used all the options available, and all had the same effect.
I stuck in a loop that ran through the ports enumerated by
CommPortIdentifier.getPortIdentifiers()
and there are only 2 of them: /dev/cu.modem and /dev/tty.modem
both of which are of "type 1" and have no "owner".

The way you phrase your question leads me to believe there is
something notoriously obvious about cu.modem, but Google is not
making anything obvious for me. Please explain.
sj


On 2006 Sep 6, at 9:59 AM, Joachim Buechse wrote:

> You are not by any chance using the cu.modem port?
>
> On 06.09.2006, at 15:26, Dr. Stephen Judd wrote:
>
>> I am trying to understand basic things about serial ports on the Mac.
>> The SerialDemo.java program from Sun's javax.CommPort program
>> displays 2 panels: characters going out to a port, and characters
>> coming in from it. Question: if I have nothing attached to the port,
>> why does anything get echoed from the outgoing panel to the incoming
>> one? My mental model says nothing should happen until there is
>> some hardware attached to the port.
>>
>> Nothing I have looked for in the code tells me there is any software
>> connection between the outgoing and incoming streams.
>> Please tell me what is broken in my brain.
>> sj