Choose one or the other, because it's rare you find a tech who is good at either, much less both.
Certifications for Nortel are done throgh Global Knowledge online and in classrooms, cost for a single cerification is ~$700-3000, depending upon course level and type of instruction.
Avaya certifications are handled through Avaya-Learning. Most courses are online, but classroom courses are critical to gaining knowledge. They're about the same, cost-wise, but have a method of accreditation that gets you certified as a tech, engineer or designer, not just sales.
A third choice would be Cisco, but their certification costs are 1/3 higher than everyone else's. But consider that Nortel is one step away from bankruptcy and Avaya is setting itself up as a buy-out target for Cisco and you can see why the money may be better spent there.
That said, there's no substitute for hands-on experience. Just like with any telecom job, watching a pro and seeing it happen in your presence is invaluable. Rarely, you'll find a place that will underpay you to learn OTJ, but you have to have a fair background before most will hire except as a grunt.
Re: meridian and lucent / pbx
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