I ran a hundred feet or so of RS232 over RJ11 (dollar-store grade). Did it for a year or two without issues. It was -12v and +12v in one direction, but just 0V

I ran a hundred feet or so of RS232 over RJ11 (dollar-store grade). Did it for a year or two without issues. It was -12v and +12v in one direction, but just 0V and +5V the other way. Just needed RX, TX and GND for our purposes. Ran at 115k2 too.