Posted by: Malcolm Jarvis

Back in the olden days (well, 2007), setting up large numbers of telephones for a call centre was a very different proposition to what it is now. Placing calls over the Internet using voice over IP, or VoIP, was a new and unproven technology, and ISDN was the standard method of equipping your office with sufficient telephone lines. This involved a hard limit on the number of conversations you could have going at any one time and was both expensive to install and expensive to run.

These days, VoIP is the technology of choice for most call centres and makes it far easier to set up, move or expand an operation. A single hosted system can provide a unified call centre platform for offices all across the globe, with each office only requiring an Internet connection in order to get up and running.

One of the most common pitfalls when setting up or expanding a cloud based call centre is underestimating the importance of your Internet connection. We’ve become so used to the idea of Internet access being just another utility like electricity and water, that it’s easy to fall into the trap of assuming that it’s just another standard item on your “new office” checklist.

Unlike standard office broadband, the type of Internet connection you require to run a call centre has some very specific requirements. Depending on the number of agents that will be using your system and the types of broadband that are available in your location, you’ll need to plan ahead in order to ensure clear and crisp phone calls that keep your agents and customers happy and allow your business to operate smoothly.

Before we look in detail at the various types of broadband available, there are a couple of key terms that are helpful to understand so you can make the best decision about what type of broadband is right for you and how much you need to spend: “contention” and the concept of  “asynchronous connection speeds”.



Contention is a measure of how many other users you are sharing the network with that carries your Internet traffic after it leaves your building and off into the big cloud that we like to think of the Internet as. It’s a lot like congestion on a motorway - it doesn’t matter what the speed limit is or how many lanes there are, there’s a point where there are simply too many cars on the road and everything slows down. If you’re using a contended broadband connection where your provider uses the same equipment to provide a service to lots of other homes and offices in your area, or if the equipment further up the chain is in need of an upgrade and is periodically being swamped with requests, you’ll find your connection speed is affected at certain times of the day.

Just to be clear, contention isn’t related to the number of PCs you have connected within your office, or sharing an Internet connection in a managed office, although the effect can be similar. It’s all about how many other customers your Internet provider and their suppliers have going over the same infrastructure as you and how heavily this equipment is being used at different times of day.

To give you an example, I’ve seen a call centre where VoIP calls worked fine for the morning and early afternoon, but every afternoon around 3:30pm, the quality of calls would drop to the point that they couldn’t operate. The problem? The call centre was situated near a residential area, and once the schools finished and the kids came home and fired up their Xboxes and Netflix accounts, the amount of Internet traffic contending the broadband connection went through the roof and meant it was no longer suitable for business traffic. The solution was to order a more “business-grade” broadband service, but the four weeks it took to get installed involved a lot of lost revenue and frustration.

While I’m on the subject, using a shared Internet connection in a managed office is typically a “very bad idea”. You have no control over the connection itself, other users in the office downloading Windows updates and large e-mail attachments can affect the quality of your calls, and a new tenant who makes heavy use of the connection can completely ruin the ability of your business to operate. If your landlord won’t allow you to install your own connection or arrange for a dedicated line to be assigned to you, I’d strongly suggest finding new premises.


Asynchronous Connection Speeds

For most Internet users, most of the time, broadband usage is all about consumption. Viewing web pages, scrolling through Facebook, watching streaming TV or films, listening to music, downloading files - these all involve content on another computer being downloaded over the Internet to your PC.

Of course, not all Internet activity is downloading - sending e-mails, uploading photos to social media sites, and making VoIP phone calls all involve uploading information to a remote computer over the Internet. However, because uploading activities are a lot less common than downloading, most broadband services provide a much faster download speed than upload speed. In other words, the speeds aren’t the same, making them asynchronous.

This is fine for general Internet use and reflects the way that most users make use of the Internet - most of their traffic is coming down the way, with only a limited requirement for uploading data and when they do, it doesn’t matter that it’s not all that fast. However, when we’re dealing with placing telephone calls over the Internet, unless you’re only planning to listen to the person at the other end, uploading is exactly as important as downloading.

If you’ve ever encountered a situation when using a VoIP telephone system where you can hear the person at the other end just fine, but they’re complaining that your voice is “underwater”, “choppy” or “you sound like a dalek”, then this is exactly what’s happening - you’ve got plenty download capacity available to bring the other person’s voice to you, but insufficient upload capacity means that your connection is struggling to take your voice to them.

For this reason, when arranging an Internet connection for your call centre, upload speed is just as important as download speed. Infact, when asking about the Internet connection at a site, I rarely pay any attention to the download speed as it’s the upload speed that is always the bottleneck.

More expensive “enterprise grade” broadband connections tend to have the same speed for both upload and download. This makes them ideal for placing VoIP calls over, but they are on the more expensive end of the scale. If the upload and download speed of a connection is the same, you’ve got what’s called a synchronous connection.


Call Centre Telephony Requirements

So, now we understand that broadband connections can be asynchronous or synchronous, and the idea that they can be contended, we’ve got the basic terminology we need to be able to understand what we’re looking for in an Internet connection we plan on running a call centre operation over.

One of the first things you need to look at is the speed of the connection that you’ll be installing. The amount of bandwidth (upload and download capacity) you need per agent will vary depending on the call centre software that you’ll be using, and your solution’s provider will be able to advise you on what you need. Greenlight’s call centre system requires 100Kbps, or 0.1Mbps for each agent that will be placing or taking calls. If you’ve not come across the terminology before, Kbps is “kilobits per second or 1,000 bits per second”, a “bit” being a signal indicating on or off that’s the basis of all data transmission, and Mbps is “1,000,000 bits per second”.

This is required for both your download and upload speed, so if you have a connection that offers 20Mbps download speed and 1Mbps upload speed, your connection can (on a very good day) support 10 users, not 200. Given that you’re unlikely to get the full speed all the time, 7 or 8 users is all that you’ll likely be able to get on this speed of connection.

It’s also important to appreciate the ways in which call centre Internet traffic requirements are a lot more demanding than general office Internet use. When you’re downloading an e-mail attachment or viewing a website, the information that’s coming down to your PC over the Internet can take a variety of different routes across the Internet and arrive in any order. That the information arrives all jumbled up doesn’t matter as your web browser or e-mail application is able to reassemble the information into the right order at your end and you’ll see the file or website correctly as soon as it’s fully downloaded.

Call centre traffic is different as in order for a conversation to flow smoothly, the audio needs to transfer rapidly and in the right order from one side to the other. There’s a very (very) small window for reassembling chunks of a call that have arrived in the wrong order into the right order before the call becomes impossible to make sense of, and you can’t buffer the same way that YouTube does as the call is happening in real time. This means that your connection needs to consistently have adequate bandwidth available for all your agents all the time, and you need to take steps to ensure that other applications on your network don’t use up your bandwidth.


How to avoid crackly calls with QoS

The bandwidth of your connection can often be consumed by other applications on your network (e-mail, YouTube, Facebook, Windows Updates etc). This means that unless you take steps to prevent other Internet traffic hoovering up your bandwidth, you’ll experience periods of crackly calls and complaining agents and customers.

Worse still, if your Wifi password becomes an open secret amongst your staff and this shares the same connection as your call centre traffic, expect your call quality to become very unpredictable indeed!

To solve this problem you can install extra network equipment that can implement “Quality of Service” or QoS (pronounced quoz), that can reserve a proportion of your bandwidth so that you always have enough upload and download capacity to ensure calls are clear. These routers can also prevent groups of PCs from accessing websites they shouldn’t, which gives you a much simpler way of preventing agents spending time on Facebook or YouTube than constantly walking the call centre floor. You need to ensure that the router you install is designed for heavy use, as cheaper equipment tends to struggle if it’s given too much to deal with. If this happens, you’ll be straight back to crackly calls, just for a different reason.


Remember when you’re ordering your connection that there’s no guarantee that you’ll get the speed advertised with most of the cheaper connection types. If you check the small print, you’ll usually see that the speed given is the maximum speed that you could get, but in reality what you’ll end up with is usually slower. This is largely determined by the distance from the exchange to your premises as the quality of the connection gets steadily worse as the copper cable connecting you to your broadband provider gets longer.

Fibre optic cable can transmit data over much longer distances without losing the quality of its signal, which is why fibre connections have much better connection speeds.

It’s possible to combine, or bond, multiple slower/cheaper connections together to achieve higher bandwidths, and in some areas this may be the only option available. You need special equipment to do this (you can’t just plug multiple broadband routers into a standard network switch), but it’s certainly an option if faster, more reliable connections aren’t available..

SLAs, as in Service Level Agreements, are also a major consideration when selecting your call centre’s broadband solution. As a general rule of thumb, the more you spend on your broadband connection, the better informed you’ll be if the connection goes down and you need to make the call on whether to send your agents on a break or send them home for the day. If you have only a few agents this may not be such a big deal, but if you have a larger call centre then this can be an expensive decision to get wrong. When getting quotes together for your call centre’s broadband, make sure you have an idea of what sort of response you’ll get should your service suddenly fail in the middle of a busy shift.


Types of Broadband Connection

So now we’ve got some terminology under our belts and have an understanding of the requirements specific to call centres, we can now look at the various types of broadband that are currently on offer.



ADSL revolutionised the way we connect to the Internet when it was introduced in the UK back in 2000. There have been a couple of upgrades to the technology since then, which you may see referred to as ADSL2 and ADSL2+, but the capabilities and limitations are largely the same.

ADSL is delivered over a regular telephone line from the exchange to your home or office and can offer fairly high download speeds of up to 24Mbps. However, as it is an asynchronous service (hence the “A” in ADSL), the upload speed is a lot slower than the download speed, usually around a mere 1Mbps or less. Depending on how far away you are from the exchange, speeds can be as low as 2Mbps download and 0.4Mbps upload, so the number of agents that can operate over a single connection can be very limited indeed.

To make matters worse, the traffic is also contended over the network that supplies the service to your premises meaning your available bandwidth can vary substantially throughout the day. For these reasons we generally don’t recommend ADSL as a long term solution for your call centre unless there are no other options available. It can be used as an interim solution while you wait for other services to be installed provided you’re prepared to live with the downsides. These downsides also include your support during outages being limited, and while this support can be improved a little by paying a bit more for a business service, your service is not guaranteed.

In its favour, ADSL is as cheap as it gets for a broadband connection. Prices vary between different providers and can be as low as £30 per month including the telephone line. Some packages have limits on the amount of data you can download in a month with hefty additional charges if you go over, so avoid these at all costs. Also, installation time can be pretty quick, especially if you already have an active phone line. If you’re in a real hurry, there’s a chance that you can pay a small additional fee for your provider to “expedite” your installation which means you could have a new line running within 48 hours of placing your order. This is subject to availability though, so it’s not something you can rely on.


FTTC or “Fibre”

This is a relatively new service introduced to the UK in 2014, that still uses your regular telephone cables that go from the green cabinet in the street to your premises, but some of the equipment that normally resides in the telephone exchange has been moved to the street cabinet so that it’s nearer your premises. As part of the upgrade process, the cable going from the exchange to the street cabinet is replaced with a fibre optic cable (hence “Fibre to the Cabinet” or FTTC), and only the connection from the street cabinet to your home or office uses traditional copper wires.

As we now know, the longer the copper cable is that your Internet connection uses, the worse the signal quality is, so a shorter copper cable results in much higher speeds than ADSL. These range from 40Mbps to 80Mbps download and 2Mbps to 20Mbps upload, but the connection is still contended with other users meaning that the quality of your connection can still be affected by Internet traffic outside your company. Again this is a cheap solution but availability is not universal and will depend on whether it has been installed in your area. Pricing and installation times are similar to ADSL and you also have the option to request an expedited order if it’s available and you’re in a hurry.


Virgin Media

This is a provider specific service that gives a fast connection (up to 300Mbps download and 12Mbps upload) at a reasonable price. They also have a business service similar to that offered by ADSL providers to give you some better support. The downside is that it’s not universally available, but is limited to areas that Virgin Media have installed their own fibre optic cable in. However, if your call centre is located in a city centre or near a large residential area, it may well be available and can be a good option provided your area isn’t subject to too much contention. Pricing for the business service is about £50 per month.



EFM, standing for “Ethernet First Mile”, is the first of what we’d consider the “enterprise grade” broadband services, and uses multiple telephone lines to deliver a faster service. As opposed to the ADSL and fibre options detailed above, the upload speed will be the same as the download speed and is usually in the region of 5-10 Mbps. Additionally, the service is not contended as much as ADSL and fibre services meaning that is less likely to have congestion during busy times.

Support is also a lot better than the previously mentioned services as it is aimed squarely at the business market, and has some resilience built in due to the number of lines used to provide your connection. You will have a minimum service guarantee that will include a maximum fault fix time, which can be invaluable when running a larger operation.

EFM is usually available in town or city centres and is available from business broadband suppliers. The only downside being the significant jump in the pricing, with the cost being around £200-£300 per month. Installation time is longer than cheaper services at roughly 6 weeks, but can be 3 months or more if there’s a need to bring the diggers in to install additional cables.


Dedicated Wireless

This is a dedicated connection like EFM, but is delivered over a wireless network. This is not to be confused with your local wi-fi connection - this is a proper enterprise grade solution that provides a high quality, stable connection to the Internet. Your provider will supply extra hardware and an aerial is fitted to the premises to connect your building to the network.

As of the time of writing, the most significant dedicated wireless operations in the UK are in Manchester and Leeds and service is dependent on availability and coverage. Pricing is similar to EFM and is similarly a sound choice for call centre traffic. The advantage of dedicated wireless over EFM and leased lines is that it’s a lot easier to set up as there are no new cables required between your office and your supplier, meaning that installation times are usually in the region of 4 to 6 weeks, but you may be able to arrange faster implementation if you’re caught short and your provider has resources available.


Leased Lines

As the name suggests, this is a dedicated line to your premises and provides the fastest speeds, the most reliable stability, the best SLAs, and as you might expect is the most expensive option available. Leased lines are business solutions and are usually managed, meaning that you’ll get extra services from your provider such as firewall management and QoS as part of the service.

SLAs typically provide a four hour response/fix and give guaranteed uptimes in the region on 99.999%. There is no contention, and these days the lines are delivered over fibre. The maximum speed of the line is usually determined by the location and can be either 1Gbps (1 gigabit = 1,000 million bits per second) or in some cases 10Gbps. However these speeds are much faster and far more expensive than a typical call centre requires, so normally you’d request a slower, less expensive service with the option to increase your bandwidth as and when you require.

For a mid-sized call centre, a leased line would typically be around 10-20Mbps and current costs are in the region of £400-£500 per month. The services are subject to survey and have a long lead time of approximately 3 Months, so you need to order well in advance of when you need your connection in place.

For some in-depth research into leased line costs across the UK, there's some great information available here.


Other Considerations

Once you’ve got your broadband connection identified, there are still other considerations worth looking at. When discussing call centre broadband, we usually encourage owners to think about their investment in their Internet connection relative to how much they spend on wages each day and how much revenue they stand to lose in the event that their operation goes down due to a loss of connection. In this way an expensive Internet connection is a lot like an insurance policy - you might not need it, but you’ll be glad you have it if you do.

It’s also worth considering installing two connections, which can optionally operate together during normal working conditions, but either can take over part or all of the call centre load in the event that one fails. For resilience of this type, you’ll need extra network equipment to take full advantage of the extra protection, and make sure that you don’t use the same provider for both connections or you’ll likely have both connections go down at once in the event of a problem!

Installing a cloud based call centre has a huge range of benefits both in terms of flexibility and cost that could only be dreamed about just 10 years ago. Getting your broadband connection right will make your business more reliable, scalable and profitable and ensure that your agents and customers are able to enjoy crystal clear calls all day long.

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