(B) CALL ROUTING EQUIPMENT:- PMBXs, PABXs, VOICE MESSAGING SYSTEMS, AND SBSs. CAPACITY (PORTS) INDIVIDUAL MARKETING PRIVATE MANUAL BRANCH EXCHANGES: ALL TYPES 4,800 9,700 PRIVATE AUTOMATIC BRANCH EXCHANGES: ONE LINE SYSTEMS, 2,500 5,000 6,200 12,500 10,000 20,000 17,500 35,000 30,000 60,000 37,500 75,000 42,500 85,000 45,000 90,000 50,000 100,000 MAX 1+4 > 1 EXCH. LINE ≤ 10 PORTS > 10 PORTS ≤ 20 PORTS > 20 PORTS ≤ 40 PORTS > 40 PORTS ≤ 120 PORTS > 120 PORTS ≤ 200 PORTS > 200 PORTS ≤ 300 PORTS > 300 PORTS ≤ 500 PORTS > 500 PORTS VOICE MESSAGING SYSTEMS AS ABOVE 98