| Manufacturer | Part # | Datasheet | Description |
 National Semiconductor ... | TP3421 |  816Kb/18P | ISDN S / T INTERFACE DEVICE WITH GCI ( GENERAL CIRCUIT INTERFACE ) |
 National Semiconductor ... | TP3420A |  524Kb/32P | ISDN S/T Interface Device |
 National Semiconductor ... | TP3420AJ |  524Kb/32P | ISDN S/T Interface Device |
| TP3420AN |  524Kb/32P | ISDN S/T Interface Device |
| TP3420AV |  524Kb/32P | ISDN S/T Interface Device |
 National Semiconductor ... | TP3420AV309 |  84Kb/3P | Engineering Project Manager |
 National Semiconductor ... | TP3401 |  249Kb/16P | DASL Digital Adapter for Subscriber Loops |
 National Semiconductor ... | TP3402 |  249Kb/16P | DASL Digital Adapter for Subscriber Loops |
| TP3403 |  249Kb/16P | DASL Digital Adapter for Subscriber Loops |