# Fast Ethernet I/O Modules

Fast Ethernet interfaces are supported on two I/O modules: the FE-8 I/O module and the FE-8 SFP I/O module.

## FE-8 I/O Module

ERX7xx models, ERX14xx models, and the ERX310 router all support the FE-8 I/O module.

An FE-8 I/O module accepts up to eight RJ-45 connectors.

## FE-8 SFP I/O Module

ERX7xx models, ERX14xx models, and the ERX310 router all support the FE-8 SFP I/O module.

The FE-8 SFP I/O module uses a range of small form-factor pluggable transceivers (SFPs) to support different optical modes and cabling distances. The I/O module supports up to eight LC-style fiber-optic connectors.

Unlike all other Fast Ethernet and Gigabit Ethernet I/O modules, the FE-8 SFP I/O module does not support automatic negotiation of the line speed and duplex mode by the router. For more information, see duplex and speed.