Line Sharing on Home Run Copper - Figure 1 ILEC Serving Wire Center ILEC Class 5 Switch Serving Area Interface Voice Copper Distribution Voice M D F Copper Feeder Voice D S L A M S P L I T E R Data Data Data + Voice CLEC Collocation Arrangement

Line Sharing on Home Run Copper - Figure 2 Data CLEC Collocation Arrangement ILEC Serving Wire Center M D F ILEC Class 5 Switch S L A Voice Common Area Serving Area Interface Voice Copper Distribution Copper Feeder S P L I T E R Data + Voice

Line Sharing on Home Run Copper - Figure 3 ILEC Class 5 Switch M D F S L A P I T E R Data Voice CLEC Collocation Arrangement ILEC Serving Wire Center Serving Area Interface Voice Copper Distribution Copper Feeder Data Data + Voice

Line Sharing on Fiber-Fed DLC - Figure 4 ILEC Remote Terminal ILEC Class 5 Switch Voice ILEC Serving Wire Center CLEC Collocation Arrangement SONET POTS P O R T Transit TC Data S O N E T TDM Circuit- Switched Voice ATM Data CLEC DSLAM/ Splitter CC2 CC1 DLC ILEC Serving Area Interface Fiber (active) Fiber (protect) Fiber (active) Fiber (protect) Voice HFPSL HFPSL FPVC/FPVP and TDM Circuit- Switched LCRTs ILEC ATM Switch/ “OCD” Data IOT IOT IOT ILEC ATM Switch PORT CLEC Collocation Arrangement TC Key: Analog Voice and Data Analog Voice only Data only Acronyms: ATM – Asynchronous Transfer Mode CC1 & CC2 – Cross-Connects DLC – Digital Loop Carrier Equipment DSLAM – Digital Subscriber Line Access Multiplexer FPVC – Fiber-Fed Permanent Virtual Circuit FPVP – Fiber-Fed Permanent Virtual Path HFPSL – High Frequency Portion of the Sub-loop IOT – Interoffice Transport LCRT – Line Card in Remote Terminal OCD – SBC’s “Optical Concentration Device” POP – Point of Presence POTS – Plain Old Telephone Service Equipment SONET – Synchronous Optical Network Equipment TC – Tie Cable TDM – Time Division Multiplexed Data CLEC Node/POP/ Other Collocation IOT IOT ILEC ATM Edge Switch Location