| ISDN-adapters external | Modem? | V.110 protocol | V.120 protocol | X.75/HDLC protocol | ISDN compression? | Distributor | Price |
| ELSA MicroLink ISDN/TL V.34 | yes, V.34 | yes | yes | yes | V.42bis | Bausch, tel. +32 16 46 12 88 | 22500 |
| Racal-Datacom DAP 6300 Lite | no | yes | yes | yes | V.42bis | ATC, tel. +32 9 371 99 99 | 25079 |
| Zyxel Elite 2864I | yes, V.34 voice | yes | yes | yes | V.42bis | ATC, tel. +32 9 371 99 99 | 27152 |
| Zyxel Omni TA128 | no | yes | yes | yes | V.42bis | ATC, tel. +32 9 371 99 99 | 17271 |
Tests performed by Data TestLab.