The Communication Unit CU801 is a unit for governing data acquisition from SAIV instrument attached on buoys/land station in the field.  All sensors from SAIV can be connected to the CU801 for live data acquisition/monitoring/recording. The Cu801 is often used together with model  TD301R for tide and water level recording.

It is based on dynamic web pages that are continuously updated by data from a connected instrument/sensor. It also send data to a file server (FTP)based on interval selected(configurable via internal webpage)  The CU801 consists of an embedded web server and network WIFI router that communicates on the global LTE/GSM network with possibility of using GPRS/EDGE/4G depend of area its placed. For displaying web pages on Internet, the web server use standard TCP/IP protocol. It has a running operating system that has a very fast boot time, approximately 0.1 second. For continuous working, the web server has a built-in watchdog. Each web server can be configured with station name and numbers of lines displayed. For changing measurement interval time and other instrument settings, it is possible to use the SD200W program to connect with the CU801 via TCP/IP(internet/wifi)

The GSM network router also has a built in web server for configuration, that can be reached when connected to the CU801 WIFI network. This configuration is password protected and is only meant for service use. For making sure that the communication is up running at any time, the router has a built-in watchdog, and always checks its connection and reconnects if connection is lost.  As in all field stations, power is always a criteria. Since the system is meant to be a "live" system there has to be power all the time. The total consumption is maximum 2.7 Watt per hour. To get CU801 on Internet there has to be a mobile telephone LTE(4G) SIM card installed in the mobile network router, only data traffic is required. GSM has normally a network range of 4 km from the coastline. The CU801 is delivered with PC-program SD200W with an IP66 box containing the web server and LTE(4G) network router, power and other installing equipments has to be provided. Normal power source is a 12 volt litium/or car battery ( 50-100 Amp) and a 160 Watt Solar panel. Litium battery is preferred  since it have 40 % more charge efficient.