As for compression, most products today are also moving toward the Stac standard, which allows routers from different vendors to negotiate compression successfully. But the situation in which you use your ISDN routers has great effect on the relevance of compression. If you're in a small office that connects directly to the Internet, compression doesn't really matter. Most images and files that are downloaded from the Internet are already compressed. In fact, with compression turned on, an already compressed file might increase download time.
Compression really comes into play in transferring files between corporate networks.
ZD Labs Internet Labs tested 12 ISDN routers geared toward the SOHO market. We required each unit to route IP, but most could also connect using IPX and AppleTalk. Although not mandatory, many products included analog phone ports, which allow for telephone calls and faxes directly over the ISDN line. Bay Networks of Santa Clara, CA, did not have units available for us to review. Gandalf Technologies, in Nepean, Ontario, was unable to ship us units in time to meet our deadlines.