DCS Gateway Keyset User Guide— 53 — The LED of the AUTO DIAL BLF key is turned on:This line is busy.Add-On ModuleThe add-on module (AOM) is used when you need more pro-grammable keys. These extra programmable keys are used inexactly the same way as the ones on your keyset. Make themAUTO DIAL or AUTO DIAL BLF keys, line keys, One-TouchSpeed Dial keys or any combination of these. A maximum oftwo AOMs can be added to any keyset.