Broadband SDSL FAQ
What is SDSL?
SDSL(Symmetric Digital Subscriber Line) allows digital data to be transferred over the copper wires currently used by the telephone system. Unlike when using a modem, which needs to convert data from analogue signalling to digital and vice-versa when transferring data, SDSL uses digital signalling therefore allowing much higher speeds of data transfer. SDSL differs from ADSL by offering the same speed up and down. For example a 2Mb ADSL connection offers download speeds of 2Mb with upload speeds of 256K. SDSL 2Mb offers 2Mb speed for upload and download.
How can my business benefit from SDSL?
That depends on how you use the internet. If you browse the web and collect email more than a few times a day and depend on the internet for your business, you should think about getting ADSL.
If however, you require live servers and fast uncontended internet access both inbound and outbound then you should consider SDSL. SDSL is perfectly suited to application hosting or servicing the requirements of teleworkers who need fast access to company systems and intranets. ADSL, while still capable of relatively fast external access is limited by the upload speed which remains at 256K. With SDSL you have upload speeds matching the download speed, giving external users much faster access.
SDSL opens up opportunities to share data with remote employees, clients and business partners and to host applications in house.
Can anyone get SDSL?
In order for you to be able to get SDSL your phone line needs to be connected to a BT exchange which has been upgraded to allow SDSL. Currently around 70% of exchanges in the UK have been upgraded, primarily in and around large cities. As well as this your business needs to be within a certain range from the exchange. If it is too far away the quality of transmission may suffer and it will not be suitable. We can carry out checks on your behalf to see if your business is able to get SDSL.
Can I connect my business network on one SDSL line?
Yes. To do this you will need to install a router which plugs straight into your network.
Contention Ratio - whats that?
From your office, SDSL connects to the local BT exchange. Then there is the connection from the BT exchange to the internet. Contention Ratio is the maximum amount of other users that can use the connection from the BT exchange to the internet at any one time. SDSL comes in either uncontended or contended form with our contended product having a 10:1 contention ratio.
For example, if you have a 2MB connection it has a contention ratio of 10:1 This means that up to 10 other companies could be using that 2MB connection from exchange to internet. Effectively this means that the higher the contention ratio, the more people are sharing the same connection from exchange to the internet and consequently, as maximum contention is reached, SDSL starts to slow down. It is very rare for all users to be using the connection at once so you can be sure that your download speed will still always be much higher that when using a modem or ISDN, which also have contention ratios.
What sort of phone line do I need?
You must have a standard BT phone line. When you order your SDSL, a line test is done which will highlight any incompatibilities. However, the following sort of lines will not work:
Lines with multiple lines off them (eg: on a switchboard or PABX system)
Lines with Redcare or Red ABC alarm service
Lines with the Caller Display CD50 service
Do I still pay for my BT line rental?
Do I still pay for outbound telephone calls on this line?
Yes. Any phone calls, modem calls or fax calls made are subject to standard BT call charges. Broadband connections are excluded though and there are no call charges to use broadband.
How long does it take from when I place an order?
When you place your order, we have BT do a complete line test within 24 hours. This will usually come back fine but just sometimes, the line quality isn’t up to scratch and your order cannot be proceed. Assuming you get past this line test (and most do) it then takes between 5 and 10 working days for BT to enable your line. Once they have done this you are live and ready to go.
Security – is SDSL less secure?
Once SDSL is provisioned y ou will be allocated a static IP address for your router. This is a “real” IP address which can be reached by people with malicious intent. It is essential therefore to protect your internal systems using adequate anti-intrusion hardware and or software.
Depending on your choice of router, you may use the router’s internal firewall or prefer instead to use additional hardware and or software to add a layer of sophistication to your security policy.
Host365 can help you to determine the level of security you need to both protect that data which is private and share that data you wish to share (with employees, customers and suppliers).
Why isn’t it available where I am?
BT has to specially enable each telephone exchange with SDSL equipment. Until it has done this, not everyone will be able to receive SDSL. Increasing pressure from government and lobbying groups is now accelerating this process. In addition, if you are more than 5Km from the BT exchange you will be unable to receive SDSL as distance is a major factor in the loss of data over the traditional phone wires that SDSL runs over.
Do you offer an engineer installed product?
Yes. All our products can be purchased for self-install and your existing IT contractor or in house team may be able to configure and install the router and internal networking and if you do have any problems, our support team is on hand to help.
We can also offer engineer installation at your premises including configuration of any PC's and network devices necessary to connect your entire office via SDSL. In addition we can provide expertise in configuring routers and any associated network components or services you need. Please call to discuss your requirements.
Can I use a wireless network with SDSL?
Yes. You simply connect your wireless gateway to your SDSL router. You will need to ensure that your wireless hardware is compatible and configured correctly and in addition consider and implement additional security to ensure your company data remains secure.