Generic HDLC layer

modulename: hdlc.ko

configname: CONFIG_HDLC

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Wan interfaces support
└─>Generic HDLC layer
In linux kernel since version 2.6.12  
Say Y to this option if your Linux box contains a WAN (Wide Area
Network) card supported by this driver and you are planning to
connect the box to a WAN.

You will need supporting software from
<http://www.kernel.org/pub/linux/utils/net/hdlc/>.
Generic HDLC driver currently supports raw HDLC, Cisco HDLC, Frame
Relay, synchronous Point-to-Point Protocol (PPP) and X.25.

To compile this driver as a module, choose M here: the
module will be called hdlc.

If unsure, say N.

source code: