You can text someone that you know is unable to verbally answer the phone at that time...but you need to let them know something. For example...I needed to update my mom while taking my stepdad's mother to a surgeon. We found out Jerry's mom has cancer and needs a mastectomy. My mom's work can record her phone calls, so she doesn't like to make personal phone calls on her work line, regardless of their importance.

So, I texted her the above information and she calls me from her cell phone when she can. That way at least she knows what is going on and isn't sitting there all frantic while working.

Hope that helps.