The Atlantic Ocean Packet Satellite Communications Network (SATNET) provides packet data transnission via satellite amg four earth stations located in the United States and Europe. The stations transmit bursts of data over a single shared satellite channel in dynamically allocated time slots under the control of dedicated computers. The burst moderns and the computers generate diagnostic and monitoring information that is transmitted via the SATNET and terrestrial circuits to the Network Operations Center (NOC) in Cambridge, MA. At the NOC, the information is reformatted and displayed by special monitoring programs. This paper describes the two SATNET monitoring programs: Mon and Ltbox, and the ways in which information from these programs is used to perform troubleshooting and system fine tuning to keep the SATNET working efficiently. These programs present satellite link and network parameters in a form that allows rapid scanning in order to extract information about the SATNET performance. Such information has been used successfully to pinpoint problems and to indicate incipient out-of-tolerance conditions of the transmissions, thus allowing for corrections before the performance of the network is affected.