Complex sentence: In this case the speeds were primarily a function of the internal clocks in the SCC, although a number of vendors provided network connectors with their own clocks that ran at much higher speeds, up to 1 Mbps.
Split into simpler sentences: In this case the speeds were primarily a function of the internal clocks in the SCC. A number of vendors provided network connectors with their own clocks that ran at much higher speeds, up to 1 Mbps.