To AvayaNovice,
Just to elaborate on the test numbers, the NXX-0049 is a quiet termination - 100 type test line -; and the NXX-0020 is a Milliwatt - 102 type test line - in the Pacific Bell "North" area and Nevada Bell areas. In the Pacific Bell "South" area the test numbers are different: Milliwatt is NXX-0002 and silent term is NXX-9298. These also work for GTE(Verizon) the original GT areas, NOT the CONTEL areas. CONTEL either had wierd numbers or none! Nothing standard. Plus there are other test numbers that for the most part have been eliminated with all the digital switching and transmission they are not needed anymore.
More: the GTE(Verizon) line ID in California is 958-1114, where you noted 959-1122 is Pacific Bell, it also looks like SBC is using this as a company wide code according to AdManOK, which does not surprise me with the changes SBC has made.
Because of the demand for special use codes like 911, 711 and 211, etc. Telcos use to use these for test numbers but NANPA has reserved two NXX codes for their use: 958 and 959. In Pacific Bell areas the ringback is 958 + THE LAST FOUR digits of your number, 2nd dialtone, hookflash, lowtone then hangup and the line should ring back. This is great for testing ringers, etc when troubleshooting. In GT land the 5ESS switches use 111+ the last four and the same format as above. On the GTD5 EAX switches it's the 7-digit phone number, ticktone then hangup and it rings!
Hope this is helpful or educational to someone!
......JIM......