noisy cable?

i managed to get hello_world working on my c121, connected through a pl2303 usb/serial cable to my macbookpro. but found that the connection is extremely noisy. often the movement of me putting down the phone on the table is enough to break the upload. is that a common problem with these headphone/serial cable plugs? for the serial device i can use /dev/cu.PL2303-0000201A or /dev/tty.PL2303-0000201A but when using the '/dev/tty...' variant, i have to add this to osmocon.c diff --git a/src/host/osmocon/osmocon.c b/src/host/osmocon/osmocon.c index f934dd7..b361eb1 100644 --- a/src/host/osmocon/osmocon.c +++ b/src/host/osmocon/osmocon.c @@ -128,6 +128,9 @@ static int serial_init(const char *serial_dev) /* hardware flow control off */ options.c_cflag &= ~CRTSCTS; + /* ignore modem status lines */ + options.c_cflag |= CLOCAL; + /* software flow control off */ options.c_iflag &= ~(IXON | IXOFF | IXANY); ============================= willem