The Honeywell V21IPUPG is a chip upgrade for older Honeywell VISTA 21iP control panels. Use the V21IPUPG to upgrade older model VISTA 21iP panels for newer Honeywell AlarmNet services.
Please note, when using the V21IPUPG chip with the Vista-GSM4G cellular communicator (Vista 21ip cellular daughterboard) the existing control panel may not be able to use the daughterboard cellular communicator.