Solution:

4WSD25OTB and 4WSD9OTB The IC used for RS232 is designed to run from 3.3 volts or 5 volts. The output voltage is rated for about -/+5 to -/+5.4 swing with a 3K ohm load. We typically see about -9 volts on a charge pump IC, but some low power port powered units 485PP9TB only swing between ground and +5.