Internal Dial Plan Part 2: Problems with Configuring Extensions on Lines

I have multiple sites with overlapping extensions. Some sites use 4-digit and others 5-digit dialing. How can I build an internal dial plan so that my numbering is simple and intuitive and users can use abbreviated dialing at their sites. This whiteboard drawing is the second in a series presenting a simple and intuitive approach for building an internal dial plan that meets those requirements. This second drawing presents problems with the simple strategy presented in our first drawing: Configuring Extensions on Lines. Simplest isn't always the best. You'll have to watch Part 3 to see the alternative strategies that fix these problems. .