Business owners can send and receive text messages with their old-school landline number using software from a Boulder startup.TextUs.Biz bills its app as the only one to essentially turn a landline into a cellphone with text capabilities. Messages are sent and received via a tablet or computer. The subscription-based service starts starts at $24 a month for up to 1,500 messages. TextUs.Biz also has a separate app that solves a problem that the company amusingly dubs the ” Person Nearest the Door Syndrome.” It turns an iPad into a digital receptionist, allowing visitors to easily check themselves in when they arrive so the person nearest the door doesn’t have to. iPad Receptionist starts at $49 a month.