The Cisco 8-Port Channelized T1/E1 SPA provides one of the greatest densities currently offered in the industry at 8 ports per SPA and up to 32 ports per SIP. At a cost per T1/E1 port less than that of a standard serial port with external channel service unit/data service unit (CSU/DSU), the Cisco 8-Port Channelized T1/E1 SPA is cost-effective for all WAN connectivity.