The SFP-10G-RA-1G-LX and SFP-10G-RA-1G-SX transceivers are rate adapting SFP+ transceivers with internal clause 37 auto-negotiation (AN) support. The transceiver host interface is 10G XFI and the module rate adapts in the egress direction from 10G to 1G before transmitting data on the attached fiber. In the ingress direction it rate adapts the received 1G data to 10G before sending to the host switch. This allows 1000BASE-LX and 1000BASE-SX support on switches which do not natively support 1G operation.