The services telecommunication engineers offer include installing, testing and repairing digital TV, satellite and fibre optic systems, mobile, broadband, and landline phone networks. A telecommunication engineer can work inside or outside, either at a client's home or business, setting up mobile and fixed communications and data networks and repair lines and equipment on mobile masts. They also find and fix faults and laying and testing underfloor and underground cabling. Telecommunication engineers often work for mobile phone and cable companies, telephone and business network providers and digital and satellite TV companies. Many also work in the gas and oil industry and railway signal engineering.