Work on call

[jessewhitelaw]

hi, I might start work for hvac/r, problem is how I can able to wake up during night time if I am on call for work for example i work everyday 7 am to 6pm and on call during night if i went sleep and how i can wake up if someone text or email me. my phone is evo htc, it don't vib long as i want. and sometime it doesn't work.. what your suggest for to must have to be prep for on call.
please let me know soon as you can. thanks