Frame Relay support

modulename: hdlc_fr.ko

configname: CONFIG_HDLC_FR

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Wan interfaces support
└─>Frame Relay support
In linux kernel since version 2.6.12  
Generic HDLC driver supporting Frame Relay over WAN connections.

If unsure, say N.

source code:
drivers/net/wan/hdlc_fr.c