You have two quite separate questions here. Was that the intention ?
1 What are the issues with telecom and data integration ?
2 What does managing telecoms involve ?
As written, the scope of both questions is too wide (for me) to give you a focused answer, but here are some thoughts.

1 What are the issues with telecom and data integration ?
a) Main issue ? technology push versus business pull. Who wants it and why do they want it ? Where are the BUSINESS requirements ? Put it another way, if the answer is “build a convergent network and run all our voice and data over that one network”, then what was the question ? I can’t stress this too much ? Business Requirements, Business Requirements, Business Requirements !

b) It is expensive to engineer your own network to give the same availability and performance of a conventional TDM. In most first world countries, conventional phone systems turn in “five nines” availability year in, year out. When was the last time you worked on a data network that was available 99.999% for twelve months ?

c) Sales and Marketing bullshit from VoIP providers. They will tell you that you can do this, do that, do the other, save here, save there etc. All of the is valid only if your organisation actually _works_ that way. Yes you can save money on calls between Head Office and branch offices if you go VoIP, because they become “free”, but if most of the calls from branch offices are to customers and suppliers and there is very little communication with Head office?. See my point. This is really another slant on technology push (disguised as “business pull”) versus genuine business pull.

d) Set up costs if you ditch your TDM PABX and put in a VoIP solution. For a start, you’ve got to replace all your digital handsets (and you’ll probably find that they are all digital if they are less than ten years old) with VoIP handsets. Those cost _lots_ of money. Money that is (usually) completely wasted. Remember most people use a phone to Take a call, Make a call, Transfer a call, Redial Last Number. Unless they work on a customer service desk, most people don’t even use Put Call On-Hold and Retrieve On-Hold Call. So buying new handsets with tiny screens that no-one uses is money down the drain. (As an aside, all new “conventional” PABXs will support VoIP if you buy their optional VoIP card)

e) From my experience, most Cisco resellers ? coming from the IT side of comms ? don’t really understand telephony. They understand the technology, but they don’t understand the application. The same may be true of you if you are from IT and have no background. eg in my experience, one of the functions many people would like is to be able to dial a telephone from the PC ? select the contact in Outlook, double-click, and “the system” places the call from your handset. Sounds like fancy VoiP stuff but it isn’t. In Australia, you buy this facility from your carrier. Telstra, Optus, Macquarie all do it. Works with a conventional old TDM PABX. So, understand that it’s all a new environment, that you’ll need to learn it, and don?t be afraid to say “Dunno ? I’ll have to find out”

There, that’s enough for starters.

2 What does managing telecoms involve ?
The most important thing ? ensure that the guy who gave you the job understands that it is a job in its own right. That it will take time (ie that you can’t do all your existing work as well) Depending on the size of the company, it could be a full time job. Ensure he also understands and ACCEPTS that you will need time / money to set up tools and processes to do the job properly, and that he will need to give you time and money right up front, so you can focus on the job and you can get it all sorted out. If he won’t accept this, then don’t take the job ? without knowledge and tools you are just making a rod for your own back

Actual work depends a lot on the how the organisation is structured, but in general:
a) relocating extension numbers when people change desks

b) cancelling old service numbers that aren’t required (the trick here is to have a threat-driven process to ensure that the bosses of the branch offices / sections that have stopped using the number actually tell you when they throw away that old fax that they never use because everyone uses email these days??.)

c) checking the monthly invoice from the carrier to ensure that:
– you aren’t being charged for cancelled lines
– you aren’t being charged from some other company’s lines (it happens, especially if your company is called Smith & Co)
– you are being charged at the rates that you have negotiated

d) It is worth while spending time when you first take on the job asking senior management (and yourself) what reports / information they need, then get yourself some budget to write a spec and have a programmer code up an application to read in the monthly invoice, process it, dump it into a database, and generate your basic monthly reports. Use a database not an EXCEL spreadsheet so you can carry out decent SQL querying ? invaluable when the CEO asks obscure questions about trends and costs. (So once you’ve go the application, load up all the old invoices too and if they have been lost, get copies from the carrier. This information is VALUABLE to you if you want to manage the telecom operation.)

e) Process: visit the PABX. Ensure every extension cable is labelled, and you can work out which service is number connects to which socket on the walls of the offices.

f) Set up a configuration spreadsheet. List every socket. List every extension Match them up ? see which should be free and check them. Every time you reallocate a number to a different extension, change the spreadsheet and add a “one-line” note on the configuration change to the bottom of the spreadsheet. Once a year / quarter, check them.

g) For branch office, do the same, but take photos of the local PABX, so you can _see_ what is plugged in where (and so you can give directions to someone else if they are swapping cables for you)

h) What about the services that don’t go through the PABX ? eg security lines, eg emergency PTN lines in case the PABX blows up Can you actually find where they terminate, and where the handsets are ? (Bottom drawer of the old filing cabinet next to Reception is often a good place to look !)

i) Finally, look at the internal phone directory. How many names (including fax lines) ? Last place I worked at had a 300 extension PABX that was full used. No spare lines. However there were only 210 names in the directory. Where did the other 90 lines go ? Couldn’t all have been used for faxes ? I was there only 7 weeks and didn’t have time to find out ? but you can see my point. You need a process not necessarily to ensure that people free up lines that aren’t needed, but to recognise which lines they have. Hint ? charging them a “rental” is always a good way to ensure unused lines get returned.

That is just scraping the surface.