Telecommunications at My office

Until about two weeks months ago, the phone systems at my company were managed by a Private Bench Exchange (PBX). Through that system there were approximately 1000 ports. Calls came in through one of the three primary rate interfaces (PRI) and routed via the PBX to phone. If someone was not at their desk, the caller would go into the Rolm voicemail system to leave a message in the individual's voicemail box. The mailboxes were spread over three servers with each box having a 50 message limit and messages being held for a maximum of two months. All local out going calls also went through one of the three PRIs. International phone calls went through a separate MCI line and national long distance calls also went through another dedicated line. At one point we did an ATM backbone to allow our office to directly connect with offices in other countries, but after a reorganization, that was dismantled

However, we are now on a new system that employs voice over IP (VOIP). It is a Cisco system that will eventually enable us to get rid of the PBX all together. Once the full system is cut over calls from the PRIs will go directly to Cisco routers. These routers will in turn send the calls through a call manager box that runs Cisco's Unity system. Unity is aptly named as it brings integrates telecom communications and our computer network. In order for a user to have a fully functioning line with a mailbox, they must also have an account on our Exchange server. Unity uses Active Directory accounts and phone numbers are now associated with them. Now when a user gets a message, the message is recorded in a .wav file and saved in their e-mail box. Since I work for a financial firm, one of the advantages for this that voice messages can be saved indefinitely. Additionally, our mail archiving server will also have a copy of any voice mail message a user receives.

One of the advantages of this new system is that calls have a couple of routers and a couple of Call Managers through which they can be routed. This means if one goes down, the company will still have use of the phones. Additionally, now user that user accounts are integrated in Active Directory, there are other technologies the company can take advantage of. Also, our networking and telecom guys can now integrate their duties. This gives the company a greater knowledge base for our current system and for further innovations.