Hi, hope someone can help me out here, I'm a linux noob with a serial port issue :) I'm running a distro called KnoppMyth R5D1. It's a Knoppix based distro designed specifically for running MythTV, a pvr program in case you need to know. I need to send a signal out the serial port (via a script) to change the channel on my digital cable box. It worked fine on previous versions but not at all on this build. I have already determined all of the hardware involved does work ( e.g. cable box accepts input through serial port, cable is good, etc.) Here's the info on my serial ports; root@mythtv:/# dmesg | grep tty serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A 00:09: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A 00:0a: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A root@mythtv:/# setserial -g /dev/ttyS[01] /dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4 /dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 3 Now following along with this howto http://www.linux.org/docs/ldp/howto/Serial-HOWTO-11.html I checked the serial port and find it appears to be blocked from sending according to this: "The transmit pin should go from several volts negative to a voltage fluctuating around zero after you start sending the bytes. If it doesn't (but the DTR went positive) then you've got the right port but it's blocked from sending. This may be due to a wrong IRQ, -clocal being set, etc. The command "stty -F /dev/ttyS1 -a" should show clocal (and not -clocal). If not, change it to clocal." Well, my signal went to about 10-12 volts positive so I'm assuming the port is blocked from sending. Checking for -clocal vice clocal shows; root@mythtv:/# stty -F /dev/ttyS0 -a speed 9600 baud; rows 0; columns 0; line = 0; intr = <undef>; quit = <undef>; erase = <undef>; kill = <undef>; eof = <undef>; eol = <undef>; eol2 = <undef>; start = <undef>; stop = <undef>; susp = <undef>; rprnt = <undef>; werase = <undef>; lnext = <undef>; flush = <undef>; min = 1; time = 0; -parenb -parodd cs8 -hupcl -cstopb cread clocal -crtscts ignbrk -brkint ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc -ixany -imaxbel -opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 -isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop -echoprt -echoctl -echoke It does show clocal not -clocal. What else could then be blocking the port from sending a signal out? The source for the channel change script can be seen here, http://www.cuymedia.net/doxygen-dev-docs/html/channel_8c-source.html Here is the specific error I get when running my channel change script; root@mythtv:/home/mythtv/tmp/mythtv /contrib/channel_changers/dct-channel# ./channel -v 10 Attempting to initialize DCT No response to packet No response to init_1; trying to continue No response to packet No response to initialize_2 Initialization failed Attempting to initialize DCT No response to packet No response to init_1; trying to continue No response to packet No response to initialize_2 Initialization failed Attempting to initialize DCT No response to packet No response to init_1; trying to continue No response to packet No response to initialize_2 Initialization failed Attempting to initialize DCT No response to packet No response to init_1; trying to continue No response to packet No response to initialize_2 Initialization failed Attempting to initialize DCT No response to packet No response to init_1; trying to continue No response to packet No response to initialize_2 Initialization failed Communication failed after 5 tries 0 root@mythtv:/home/mythtv/tmp/mythtv/contrib/channel_changers/dct-channel# Thanks much, If anyone can help I'd really appreciate it, and if you need any more info just ask! Kamy - To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
