Departments organize a business phone system into separate areas, each with their own number, schedule, voicemail, and routing rules. A small consulting firm might have departments for "client-facing", "operations", and "billing". An agency might have a department per major client. A clinic might have departments for "front desk", "scheduling", and "after-hours".
Department numbers route independently — sales might be staffed 9–6 with a hunt group across three reps, while billing is one person Mon–Wed with after-hours voicemail. Members can belong to multiple departments without being charged for multiple seats.
In Kelir Team plans, Departments are a first-class concept: provision per-department US business numbers, set working hours and IVR per department, and assign team members to one or more. Managed from the web portal at app.kelir.io.