Implementing a Low Cost Voice over IP System at a Small Private School
Voice over IP (VoIP) is continuing to grow in leaps and bounds. As the technology matures, the equipment required to support it becomes cheaper and easier to operate helping smaller organizations adopt the same technology enterprise customers have been enjoying for years at significantly lower costs (both in hardware and support.) One such example of a small organization benefiting from the deployment of VoIP is a local private school that where I volunteer and serve on the technology integration committee.
The decision to evaluate other options for a phone system came after the school had already accepted the donation of an old key system from a local business and paid a local telephony contractor to install the system. After spending many costly hours programming the hardware, the system could send and receive calls but the phones were difficult to operate and voice mail didn’t work. In addition to this, every time a change needed to be made to the system, the contractors would need to be called and because of the age of the system, any additional hardware needed to be purchased on the open market and since the hardware was system specific it could be quite expensive.
A school has different requirements than a business does for phone systems and it was this realization that led the technology committee to recommend implementing a VoIP system to the school board. Since this was a small school, cost was a primary consideration. By implementing a VoIP system, we could utilize the existing network infrastructure. This particular school has the benefit of being in a newly constructed building with brand new Cat5e wiring with at least 2 drops in each room. VoIP systems are also easier to support by non-expert users since they utilize web interfaces for managing extension assignments, voice mail, etc. The ability for the school’s tech. admin to make simple moves/adds/changes to the system without incurring any cost or waiting for a member of tech. committee’s time would reduce the time it takes to make changes to the system and would result in further cost savings. Another requirement considered was the fact that teachers move around the school constantly so providing the school secretary with easy call routing capabilities was a necessity.
With cost being a primary consideration, we on the tech. committee have learned to make do with equipment donations from friends of the school so we began scouting for pieces of a VoIP system that we could consolidate into a real working system. For call processing/handling software we decided to go with AsteriskNOW because what price can be better than free and we were able to acquire an older HP DL380 for it to run on which provided plenty of processing power. Since AsteriskNOW primarily supports SIP we started looking for SIP-capable IP phones to go with the system starting with used and off-lease Cisco IP phones but we were eventually able to find a sufficient quantity of Polycom IP430 phones a company was willing to donate along with a Polycom IP601 for the secretary.
From the network hardware perspective the school would be in pretty good shape were it 3 or 4 years ago. Their switching infrastructure consisted of 3 Cisco 2900XL switches and 1 Cisco 2950 and their firewall was a Cisco PIX 506e. They utilized a single VLAN and one /24 subnet. In order to segregate the voice traffic from the rest of the network we decided to add another VLAN on top of the existing network. Since we had no layer 3 switching capabilities and our firewall only supported 2 fast ethernet interfaces we added a Cisco 1721 in a router-on-a-stick configuration to route between our two VLANs since our donated 1721 only had one physical ethernet interface. In addition to the 1721 we also had another 2950 switch donated which gave us enough ports in our server room and IDF that supported QoS for the amount of phones we were going to have.
Since the phones were donated, not all of them came with a complete set of accessories, particularly power adapters. Thankfully all of the phones supported Power over Ethernet (PoE) so we were able to purchase 2 PowerDSine 3012 PoE midspan devices, one for the server room and one for the IDF, to push power out to any phones that didn’t have wall adapters or weren’t close to an electrical outlet.
For trunk lines we evaluated the option of purchasing a SIP trunk but the school is only fed through a business-class DSL line that wouldn’t provide sufficient upstream bandwidth so we elected to stay with the current analog POTS lines already coming in to the school and add a card to our server that would support multiple FXO lines. Since we were using AsteriskNOW we decided to purchase the Digium TDM808E card which would support up to 8 incoming lines. Configuring the card to work with AsteriskNOW was almost too easy. There’s an “Add Hardware” option in the web interface that automatically detected the card. All we had to do was specify which interfaces had incoming lines connected.
Based on conversations with the secretary and school administrators we came up with a call routing plan that met everyone’s needs. The old phone system would simply simultaneously ring all lines whenever a call came in so those not wanting their phone to be ringing continuously would simply turn their ringers down or off. With the flexibility of Asterisk we were now able to set up directed call routing paths to groups of users instead of the entire user base. Since teachers would likely be lecturing most of the school day we set up a call group in the main office to ring for any inbound call. If the staff in the main office is busy or unavailable the call would roll over to an auto-attendant and allow an extension to be dialed manually. If an extension isn’t dialed within a few seconds the call rolls in to a general voice mail box that will trigger the message waiting indicator on all of the office staff’s phones.
When all was said and done the system cost the school about $1200 to install. If we hadn’t gotten so many donations the system would’ve cost about 4x-5x more depending on hardware choices but even that would’ve still provided a cost savings versus paying a contractor to come out every time we needed changes made to the system. In addition to reduced labor costs the school now has a very modular, flexible system that doesn’t rely on a central “black box” proprietary solution. We can add any SIP-capable IP phone including wireless ones, we can add more analog phone lines, and we can modify call groups or ring assignments with a few clicks. With a solution such as this, small businesses, schools, churches, or charities can have a cheap, simple, scalable, flexible phone system that they can manage on their own without the need for costly contractors and proprietary equipment.
Leave a Reply