Data Transmission Mode : In the case of data transfer from source to destination, the direction of data flow is called data transmission mode. The data transmission mode can be divided into three parts based on the direction of data flow. Namely: 1. Simplex II . Half - Duplex Full -Duplex Data Transmission Method : Data transmission refers to data transfer or data transfer. In order for data to be transmitted, there must be a definite method between the sender and the receiver , this method is called data transmission method. The data transmission system can be divided into two parts based on the cable connection. Namely: 1. Parallel Data Transmission Serial Data Transmission