Cisco ISR

The Cisco Integrated Services Router (ISR) is a 2U platform designed for dense routing applications where size matters. This chassis was originally designed as a branch office router and was introduced to the Cisco product line around 2004. The hardware reached end-of-life in 2011 and passed end-of-service-life in 2016 per Cisco's listed policies.

The 3825 is used in the SneakyNet system to provide both IP data services as well as to serve as the TDM switch at the Telco end of the connection. The router contains multiple T1 interface cards, and has an NM-ESW16 card which provides an onboard 16 port switch.

The 3825 provides the network clock for the T1 connections which are synchronous serial links. The clock on the 3825 is allowed to free-run relative to network time, however proper ISPs make use of extremely high precision clocks to maintain a precise lock against the long distance network's clock. The IP throughput capabilities of the 3825 chassis are laughable by today's standards, but would have been fairly impressive when it launched. While not in use by SneakyNet, the 3800 series routers support Cisco's proprietary DC feed standard for a secondary power supply, which would have enabled the router to consume power from either a standard AC bus or from a variety of secondary sources in the event of a mains power failure.