The ITT 76A was an advanced 1A2 KSU made in three different versions with capacities of:
7 lines, 18 phones, 2 intercom links14 lines, 36 phones, 3 intercom links20 lines, 54 phones, 4 intercom links
Each intercom link appeared under a specific button on the phones. Intercom calls could be announced with tone ringing, or call announcing with handsfree answerback. Handsfree intercom calls were limited to 16 seconds or 32 seconds. Longer conversations used the habndset.