In spite of other communication service such as e-mail as growing Internet, the mail is fast growing. In process of mail service, the delivery sorting process is a bottleneck due to its time assuming work. Delivery Sorting System (DSS) sorts the mail by delivering order in high speed real-time process. The existing DSS is based on QNX with own network. QNX is real time OS based on POSIX. QNX RTOS is robust from tiny embedded device but it is expensive and is difficult to maintain. The suggested system based on Linux / Embedded is Flexible and economy due to open source.