Tummala Electronics Pvt. Ltd. Manufactures Dual-Tone Multi-Frequency Way Station Telephone. Tummala Electronics Pvt. Ltd. Offers Railway Communication Equipment, Solar Water Heaters and Solar Powered Lighting Systems. The Dual-Tone Multi-Frequency Way Station Telephone is used to facilitate communication between a train controller and way side stations in both 2 wire & 4 wire areas. It is housed inside a desk type telephone cabinet. It consists of a DTMF Receiver, Code Setting and Group Call DIP switches and associated logic circuitry.