This compression is not just available in Cisco routers. In fact, most any router will support this type of compression, albeit that they may require an expansion card.

It is also available for Linux on ISDN connections. The source code is in the isdn4linux CVS tree (
Not all ISPs support this technology, but the speed increase is very noticeable. Expect anything in between 15 to 75 kb/s on just one ISDN channel (64 kilobit) for uncompressed data (text or html for example).