FEATURES- High Speed Parallel Line Extender The parallel interface has a serious limitation in that data can only be transmitted reliably over relatively short distances. This problem is solved with the lightweight, easy to use, IC-164T/ IC-164R (Transmitter/Receiver) line extender pairs. The speed of the IC-164 outperforms any available product of its kind, and use of 4 wire telephone line virtually guarantees error free transmission. * No External Power Required (External Power Optional) * Can Be Used With Auto Switches * Easy Installation * Compact Size * FCC Approved "