Performance of Cat 3 and Cat 4 cables
Category 3 is the performance level for voice and data transmission up to 16 MHz or 10 Mbps, such as 4-Mbps Token Ring and 10BASE-T.
Categroy 4 is the performance level for voice and data transmission up to 20 MHz or 16 Mbps, such as 4-/16-Mbps UTP.
Both Category 3 and 4 are unsuitable for today’s high speed networking standards and will need to be replaced with Cat5 cable as a minimum if you intend to run 100baseT Ethernet.
Category 5 and 5e cables