Eppflex
Eppflex is a hardware interface for the Centronics interface (LPT port) of a computer. It is a packet radio controller that is used in amateur radio to operate a packet radio station.
In addition to the computer, it is connected to a modem , which in turn is connected to a transceiver . Depending on the transceiver, you can use baud rates from 9600 baud up to more than 1.2 Mbit / s. In amateur radio, the interface is used for data transmission , for example for access to a broadband entry point of a digipeater. The high speeds cannot be achieved with serial interfaces on computers, so the parallel port was used. The interface is available as a kit or as a finished device. These could be modified according to your own wishes. There is also a USB version.
The EPP interface contains the hardware required for data exchange with the parallel port, two IDT FIFOs with a storage capacity of 2 kByte and a converter from parallel to serial interface. In the receive path, the data is synchronized and in the RX - FIFO written. There the data can be transferred to the parallel port with "normal" EPP read instructions. In the send path, the parallel 8-bit data is written to a TX -FIFO. From there, the data is read out sequentially and processed as a serial data stream by the externally connected modem for transmission.
The EPP interface is currently only supported by the FlexNet system. The software for other software architectures is still under development.