This system supports 8 lines by 24 extensions, and can be expanded up to 128 ports on a combination of lines and stations, up to a maximum of 80 co lines or 120 stations or a combination of the two. It can be customized, and expand with your business! This model is discontinued by Nortel, has these in stock. Many of our customers are very happy with this system. And since it is a discontinued system, we can sell this high quality system to you for a low price!