The LDK range of controllers include:
| Model number | Lines & Extensions | Comments |
|---|---|---|
| LDK 20 | 20 | Flexibly used lines and extensions (called ports) |
| LDK 50 | 50 | All systems can handle Analogue lines |
| LDK 100 | 100 | All systems can handle ISDN2 |
| LDK 300 | 300 | All systems can handle ISDN30 |
| LDK 600 | 600 | Maximum capability for this range |
The upgrade path is via improving the processor and using a larger chassis ( to store more cards)
Making the upgrades is via a series of plug-in cards. These include:
- SLIB cards: add up to 4 analogue phone lines into the controller with this Single Line Interface Board.
- STIB cards: add up to 2 ISDN 2 lines per card
- DTIB Cards:
- VoIP Cards: To add SIP trunks / VoIP between like systems.
