I/O Link Extenders provide the ability to locate a single IOP card file, or a complex of IOP card files, with IOPs and attached FTAs up to 8 kilometers (5 miles) from the HPMM. Two types of I/O Link Extenders and their associated fiber optic couplers are available, the 'Standard' I/O Link Extender with up to a 1.3 kilometers link, and the 'Long Distance' I/O Link Extender with up to a 8 kilometers link. The connection is made using a pair of fiber optic transmission cables, driven and terminated by a fiber optic coupler that mates with the connector located directly below the I/O Link Extender card in the card file.

Each I/O Link Extender consists of two I/O Link Extender cards, one for Link A and one for Link B, that occupy two slots in the HPMM and IOP card file.

Each Long Distance I/O Link Extender card has an associated fiber optic coupler that drives a single pair of fiber optic cables. Each cable pair is terminated by a fiber optic coupler that terminates one fiber optic pair.