Problem Make Speedometer with Hall Effect Sensor and RF-RS232

Hello,

I want basic telemetry system and i will send voltage, current, speed and temperature values this system. I have 3 questions about this situation.

First Question:
- 18F4550 has one rx one tx inputs. I want to use together RF and RS-232 communication on receiver card. I use microcontroller' s tx-rx inputs for RS-232 communication and whatever inputs for Dorji RF (DRF 7020D27). For example as a Symbol TX PORTC.0 and Symbol RX PORTC.1.

Second Question:
- I have hall effect sensor' s code for speedometer as follows and i don't understand this code. Could you explain this code for understanding?

speed_Measurement:
pulsperiod = PulsIn PORTD.7,0
temporary1 = 250000/pulsperiod
speed =temporary1*2.772 ;5.544 for 4 magnets
speed1=speed

And Finally:
- I think ACS755-150 for current measurement but how i don' t know high DC voltage values. For example as a 150 VDC.

Already thanks a lot for yours help :)