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VoIP equipment deployment essentials

Starting this week and in the next two instalments, we continue discussing Voice over Internet Protocol (VoIP) due to its importance as an essential business communication tool. From last week’s article, we now know what VoIP is, but then what equipment do we need to deploy it? Remember, VoIP, combined with least-cost routing, helps reduce telephone calling costs by over 50%. Typical VoIP networks — no matter how small — will have the following elements: an internet protocol private branch exchange (IP-PBX), IP phones, Analogue Telephone Adapters/VoIP gateway, GSM (mobile) gateway, PSTN (landline) gateway, soft phones and, of course, a network which can be Ethernet or fibre optics or wireless. In this discussion, we will explain each of those components where they come in your VoIP/PBX deployment.


An IP-PBX is right at the centre of your VoIP deployment. An IP-PBX is a computer system that handles your incoming and outgoing calls in an intelligent manner. It is a combination of hardware and software, running call switching.

You can legally run your own private IP-based telephone network for your organisation without having to traverse into any GSM, VoIP or landline network. This is very useful in saving costs of making telephone calls.

The IP-PBX systems can be used for private internal networks or to connect to external networks via use of gateways. The size of the IP-PBX you get will be determined by the number of users you plan to have on your network. The all-in-one IP-PBX solutions generally have registrar, proxy, voice mail, presence and instant messaging (IM) server.

IP phones

An IP phone uses VoIP technologies allowing telephone calls to be made over an IP network, such as the internet instead of the standard PSTN system. Calls can traverse the internet or a private IP network such as that of a company. This means when you get an IP-PBX for your telephony needs, plug in any type of IP phone that supports Session Initiation Protocol (SIP).

IP phones have an Ethernet port that simply plugs into your existing network. Standard VoIP calls usually have two ports where you can share your internet connection between the phone and your PC without the need of extra cabling.

ATA and VoIP gateways

An analogue telephone adapters (ATA) and VoIP gateways are devices used to connect one or more standard analogue telephones to a digital telephone system (such as VoIP) or an Analogue PABX system. This means that when you are deploying a VoIP system, you can still use analogue telephone handsets with ATAs/VoIP gateways. You simply plug in your analogue phone into the ATA/VoIP gateway.

The ATA/VoIP gateway has an Ethernet connection on the other end that connects you to the IP network, be it private or public internet. There are two types of ATA/VoIP gateway connections — FXS and FXO. What you need to know is that with the FXS you connect regular phones to the device and with the FXS you can connect the device transparently to TelOne, which is the landline (PSTN) provider in Zimbabwe.

GSM gateways

GSM has emerged as a superior alternative to the fixed-line networks and offer wider coverage, has less incidents of vandalism and call costs are relatedly less.

Today’s businesses expect the specific benefits from GSM networks without sacrificing existing landline connectivity. A VoIP GSM gateway enables direct routing between IP, digital, analogue and GSM networks. With these GSM devices, companies can significantly reduce the money they spend on telephone calls, especially on calls from IP to GSM. The core idea behind cost-saving with VoIP and GSM gateways is least-cost routing.

Through least-cost routing, the GSM gateways select the most cost-effective telephone connection, to any destination worldwide. The IP-PBX checks the number which is dialed as well as call rates, which are stored in the IP-PBX routing table. Since SIM cards from different networks are integrated within the VoIP GSM gateway, it is able to make relatively cheaper GSM-to-GSM calls.

To archive least-cost routing, one invests in a multi-channel GSM gateway, connect it to the IP-PBX and then source SIM cards from the local GSM network operators namely Econet, NetOne and Telecel. The result is massive telephone call savings, as the IP-PBX chooses the cheapest SIM card to make a call to any destination, local and international.

This article is published by Standard Global Communications (SGC). The company has been deploying telecoms and electronic security solutions in Zimbabwe for over 20 years. SGC offers free consultation, designs, deploys and provides after-sales support. Our flexible and scalable solutions help reduce telephone costs, while increasing operational efficiency at an affordable cost. For inquiries or more information, questions and comments, please call: +263 242 790 791-5, mobile: +263 772 875 577, e-mail info@standardglobal.co.zw or follow us on Facebook, LinkedIn, Twitter or visit www.standardglobal.co.zw for more or if you wish to download this article.

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