HDLC#1 - Header Compression

Configure header on HDLC link:

R2(config)#interface serial1/0
R2(config-if)#compress ?
  stac  stac compression algorithm
 

R2(config-if)#compress stac
R2(config-if)#end
R2#

This is for header compression, not for data compression.

Must be configured on both sides.