I have a nortel norstar 3x8 dr5.1 and have 2 t7316E's and 3 t7208's. The t7316e show the lines and the extensions and which extension is using which line, but for some reason the t7208 will not. I have the lines programmed to the keys and several of the extensions to the phones also. I want it to show which extension is using which line. I know this is probally a simple fix.. Please help....