While the operation of different facilities, which are connected to a computer via serial port, there may appear the necessity to start up utility program (for these facilities) not in the machine, to which the facilities connect directly, but in the remote machine, that is connected to the facility server via the network (TCP/IP). The developers of the given facilities very often face with such a necessity. For instance, during the debugging in a remote machine or when different people with the help of different machines (which are nevertheless connected to one machine) maintain the same facilities. HNSD is designed especially for the solving of these problems. The use of our product gives you the possibility to give the remote access to serial port via TCP/IP. The product consists of three parts: 1. NVSD is a program emulator of serial ports (up to 255) for operational system W2K/XP. 2. HNSD client is the service, which realizes the exchange between NVSD and TCP/IP. 3. HNSD server is a service which realizes the exchange between a real driver of the serial port and TCP/IP. HNSD client and server handle two flows: outcoming and incoming. The client takes the bytes that were transferred to all the virtual ports earlier and then transfers them to the server, which was started up on the other computer. Also the client receives flows from the server and gives the bytes (as those which came from the outside) to NVSD. IP address of the receiving server, port number and the number of the real serial port on the receiver are specified on the client for each port. The server receives the information from clients and then transfers it to the ports specified by them. As for the flows, which came from these ports, the server transfers them to the client as well. Besides the data flow, TCP/IP transfers the overhead information about the condition of different signals on serial port physical contacts.