Meridian Mail was one of the early all-digital voicemail systems, running on Meridian Norstar digital PBX systems from Northern Telecom (later known as Nortel). In the early 1980s Northern Telecom introduced the Norstar, a scaled-down version of their SL-1 all-digital switch. The Norstar was the first all-digital system suitable for small-sized offices (up to 192 lines), and became one of their major product lines. CallPilot was one of the products acquired by Avaya in their purchase of Nortel Enterprise Solutions in 2009.