Figure 6.2: Internal PBx-Based Telephone networt Private Branch eXchange 专用(分组)交换机 4. Termination 5. PBX 7 Vertical 3 Equipment Internal Telephone Riser Entrance Switch Space Facility ■|■ 2. TO 6. Wire Telcos Bundle (Many Pairs) 1. Equipment Room(Usually in Basement) 6-46-4 Figure 6.2: Internal PBX-Based Telephone Network 1. Equipment Room (Usually in Basement) 2. To Telcos 3. Entrance Facility 5. PBX Internal Telephone Switch 6. Wire Bundle (Many Pairs) 7. Vertical Riser Space 4. Termination Equipment Private Branch eXchange 专用(分组)交换机