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The Physical Layer of VoIP

A basic rule when laying out networks starts with separating voice and data cabling with white and blue respectively. It's red all over when you do not physically separate networks for management of successful VoIP implementations.


telecom-datacom-toolkits Tools for the Trade

Having the right tools, gets the job done right

Toner & Wand

Tone Generator and Probe (Wand) to find cables by adding noise and identifying cables via tones. Tone and trace wire on non-active networks. 

Cable Tester


Displays cable length, wire-map, cable ID, and distance to fault. Detects today’s media services, including 10/100/1000 Ethernet, POTS, and PoE

Electrician Scissors


Electrician's Scissors are made of tough tempered steel and feature a free-fall snip design for greater ease of use. Cuts 19 and 23 AWG electrical communication wire.

Punch Down Tool


Impact Punch Down Tool For seating wire into terminated blocks & cutting off wire end after termination.

The Physical Layer Possibilities


  • * Cabling (Patch Cords, Patch Panels, Jacks/Outlets, Noise on Cable, etc)
  • * Connectivity (Hubs, Switches, Routers)
  • * Power (Breaker, Fuse, UPS, Test for Power)


Troubleshooting errors at this level include using cable testing tools to ensure cabling is functioning properly. Link lights on network devices are also a great way to troubleshoot issues at Layer 1. If the link light is green, then Layer 1 is working. If the link light is another color or not lighting up at all, then there is a problem at this layer. Easy ways to test this are swapping out cables with a working cable, swapping SFPs, or modules, and using cable testing. Cisco provides a tool in the IOS to test 10-Gigabit Ethernet or copper links using TDR. To do so, one would enter the test cable-diagnostics tdr interface type number privileged EXEC mode command. One can also troubleshoot modules or interfaces by using the show interface, show module, or show test commands.





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