Cabletron Systems Inc.

In 1993, Critical Technologies developed a ‘cable modem’ for Cabletron Systems Inc. (a Fortune 500 networking equipment manufacturer). Our design remotely and transparently bridges Ethernets over legacy metropolitan area broadband cable TV plants. It segments IEEE 802.3 packets into ATM cells; scrambles, Forward Error Correction (FEC) encodes and frames those cells; acquires access to the physical medium using a Demand Assigned Multiple Access (DAMA) protocol; and transmits over the radio frequency (RF) medium.

CTI performed this effort in its entirety: we determined system requirements in consultation with our clients, their customers and their subscribers; we investigated both previously attempted and new architectural approaches to meeting those requirements; we enhanced existing protocols and developed new ones as necessary. We designed, coded and debugged the software; we designed, fabricated and debugged the hardware; and we integrated software with hardware. We field tested and demonstrated functioning prototypes, without interference to or from other services (including premium channel pay TV programming) operating in immediately adjacent channels on the same real-world operating CATV system.