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setting up a serial loopback connection

Posted: Sun Jan 24, 2010 1:59 pm
by goaskin
There are lots of discussions about the terminal service provided on the serial port of the TV if a terminal is connected. Because not everyone wants to connect a computer directly to the TV, it would be great if there would be a way to simulate this connection to make the service accessible with a terminal program like minicom what is installed directly on the TV.

Has anybody an idea how to establish a loopback serial connection by bridging two device nodes internally? For example, you open minicom, use port /dev/ttyS1 and get an output like /dev/ttyS1 has a cable-connection to /dev/ttyS0?

Re: setting up a serial loopback connection

Posted: Tue Jan 26, 2010 2:33 am
by erdem_ua
Hi.
I tried with minicom and it gives error. I think it complained about no termcap file...
Anyway, I search and found picocom utility, also you can found Debian Armel binary in package.
I tried on /dev/ttyS0 but it looks like don't transmit any data.
I realized that TV has 6 tty device. /dev/ttyS[1-3] and /dev/ttySD[1-3].
When I connect dev/ttySD1, I see some lines at kernel messages via dmesg command.

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# dmesg
<1>[SERIAL INPUT MANAGE] Managed tty_struct(.name:ttySD1) Setup!!!
<1>[SERIAL INPUT MANAGE] disable_serial : ~~bye(len:5)
<1>[SERIAL INPUT MANAGE] enable_serial : debug(len: 5)
<1>
But I cannot use this connection as a debug menu like input. When I kill picocom program dmesg putt some extralines too

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<4>recovery console port ISR 
<4>Debug port shutdown 
<1>[SERIAL INPUT MANAGE] Managed tty_struct(.name:ttySD1) is freed !!!
I don't know what is those ports, might be for gdb like debugger?