The benefit of ISDN is its reliability of service, and if you intend to use your video conferencing for mission critical events than ISDN should definitely be considered as a primary or secondary network.

IP networks are now at the stage of being able to provide the bandwidth and low latency requirements that are needed for video conferencing. Because video conferencing is about the transmission of video and audio in real time, latency issues can adversely affect performance to the point that the call is unacceptable or can’t be maintained.

When using IP networks for video conference equipment, it is recommended that you utilise a business grade service and that the service can support the required bandwidth including data overheads. This can cost even more than ISDN depending on the service and so a feasibility study should be conducted.

Utilising IP networks does have its shortfalls and one of those is the ability to connect to an external site. For example, if you were a law firm that used videoconferencing between your offices, you would find that your videoconferencing would work fine, especially if you are utilising an existing Enterprise grade Wide area Network between your offices. However if you were to call an external client who also has video conferencing equipment you might find that their internet service provider does not provide a very good pipe (Connection) to your provider and you may experience latency (length of time it takes for data to arrive) and bandwidth (The amount of data you can send) issues.

This is where an ISDN service works extremely well as it is what is called a switched network with a guaranteed level of service.

So how do you get the best of both worlds?

Most codecs these days will support both networks so supporting both technologies is not an issue but you don’t want to spend lots of money installing both networks. If the majority of your conferencing will be between your offices and you already have an extensive IP network in place then IP is the way to go for these types of calls but occasionally if one of your offices require the ability to call an external site over ISDN then you can install one of these services to accommodate.

All your internal calls will cost minimal or will be free dependant on your IP infrastructure provider and on the odd occasion that you do make external ISDN calls you will only pay for the time you use.

Another way of saving money when using ISDN services for videoconferencing, is to share an existing infrastructure. ISDN has more than one use other than video conferencing; it is more commonly used for your telephone lines and terminates into your PABX equipment.

If you happen to have one of these services you may be able to accommodate ISDN extensions on your PABX which means that you no longer require a dedicated service for your video conferencing equipment. However your videoconferencing equipment will utilise these lines when it requires them and they will be unavailable for use while in a conference much the same way if your incoming lines were busy taking voice calls.

ISDN comes in two flavours, a Basic rate service “BRI” and a Primary rate service “PRI”. It is pretty easy to determine what service you are using because a BRI service supports 2 lines where a PRI service supports 10, 20 and up to 30 lines. So if you have 10 lines or more, you will most likely be running a PRI service.

This is not to be confused with how many numbers you have as with ISDN services it is common to have what is called an in-dial which is a number range. For example, you could have an in-dial range of 100 which means you have 100 numbers in your range. It might look something like this: (07) 3620 7300 – (07) 3620 7399. If you have a PRI 10 service with an in-dial range of 100 then you can receive a maximum of 10 calls simultaneously on any one of the 100 numbers in your range.

Video conferencing will not work over a single line, in fact the bare minimum requirement is 2 lines which equates to 128 Kbps (Bandwidth). To achieve a reasonable picture and audio quality a bandwidth of 384Kbps is recommended. This is the equivalent of 6 lines and if you are utilising a PRI 10 service you will be occupying 6 of your 10 lines to achieve this.

Your call costs will also increase as with ISDN you pay per line. Videoconferencing calls are considered ‘data’ calls when using ISDN and data calls are generally charged at a different rate to voice only calls.

If a data call from Sydney to Melbourne was to cost .50 cents per minute than a video conferencing call at 384Kbps would cost $ 3 per minute & at 128 Kbps it would cost $ 1 per minute. Of course this is only an example and actual costs would be dependent on what your carrier charges for data calls over ISDN.

What you should have realised by now is that video conferencing does require some forethought and planning before implementing a solution.

Rabone Systems will provide you with all the necessary information as a part of the video conferencing solution, making sure that you benefit from the cost savings of videoconferencing over traditional travel costs as well as getting a return on your investment.

Video conferencing has been around for more than a decade and back then there was limited players in the marketplace and systems were very expensive to install as well as call costs over Telstra’s ISDN network as IP was not an option.

The key thing to remember with video conference equipment is that it should be complying with a global standard. This ensures that you get trouble free conferencing between different manufacturer’s codecs but in the real world this is not always the case.

How to avoid potential compatibility issues can be done as simply as using a manufacturer who has extensive experience and market share in the video conferencing arena.

In Australia, the major players are Polycom, Tandberg & Aethra. Polycom would have the majority share of the market but it does come at a premium price and may not fit into your budget.

Aethra which is an Italian company have been gaining serious traction in the market and do offer a very economical solution to the SME marketplace without compromising performance.

Rabone Systems offers both Polycom video conferencing and Aethra video conferencing equipment to its clients and we can provide a full integrated boardroom solution or training facility utilising a control system such as AMX to provide simplicity of operation.

Once you have established which platform and features you like, the type of network you will utilise will need to be decided.

Rabone Systems has extensive experience with Videoconferencing and can provide you with the correct answers so you can make the right decision