ISDN Vs VOIP - 03/09/10
Posted by Cloud Net on Fri, Sep 03, 2010 @ 08:13 AM
Most business phone systems are delivered via one of two
technologies: ISDN or VoIP. Both ISDN and VoIP allow the connection of a private branch exchange (PBX) – otherwise known as a switchboard – to the external telephone system. You may be considering which to use to carry your phone traffic so let’s compare and contrast these alternatives.
ISDN
ISDN was first widely used back in 1988 and in the days of dial-up modems, ISDN was the first commonly available ‘broadband’ service, offering speeds of up to 128kbps. ISDN offered phone companies a way of sending digital data over the public telephone network. Today, ISDN for comes in two main flavours.
• ISDN2e
ISDN2e is for small businesses that need two or more telephone lines to handle their communications. Each ISDN2e line provides two channels of ISDN, each channel operating at 64kbps speed. The two channels can be bonded together to achieve a speed of 128kbps. This technology is largely unchanged from that first rolled out back in 1988: it used for on site PBX’s.
• ISDN30
ISDN30 is mainly used by medium to large sized businesses with a telephone system (PBX) on their premises that require their voice and data to be delivered as a single service.
Each ISDN30 service has a bandwidth of 2Mbps and is provided into your premises from your local BT telephone exchange over either a copper or fibre circuit or via a radio connection. An ISDN30 service comprises of 30 independent 64 Kbps channels, plus two further channels, which are used to manage the service. When newly provided, at least eight of the 64Kbps channels must be activated (and paid for) by the customer.
Additional channels can be provided when required. When you reach the position of having 30 channels operative but need more, a new ISDN30 service can be delivered and linked, providing up to another 30 channels.
VoIP
VoIP stands for Voice over Internet Protocol and is a general term for a family of methodologies for delivering voice communications and multimedia over the Internet and other Internet Protocol (IP) networks. In effect, the telephone and multimedia service is delivered via a broadband connection.
VoIP technologies allow the PBX to be sited within your business premises or externally.
The more traditional PBX solution relies on the PBX being on your site, handling the switching and passing the traffic into the internet using so called ‘SIP trunks’, which are purchased from a SIP trunk provider. The SIP trunks are virtual circuits configured by the provider to mimic a conventional telephone system.
The external PBX solution relies on connecting phones directly into the Internet and then handling the traffic with a computer that mimics a traditional PBX. This is called a hosted service. The hosted service allows you to have no hardware on the business premises except for the phones themselves. The phones have to be special IP phones and Cloud Net provides these IP phones to customers at not cost to encourage them to use the system. The external, hosted system is gaining greater acceptance all of the time and has a great number of benefits, particularly cost, over the traditional service and we will concentrate on this in the comparison table that follows.
Comparison
| ISDN |
Hosted VoIP |
| High install costs from BT |
Low install costs |
| Dedicated channels need to be paid for whether used or not |
Complete flexibility in number of channels required |
| Traffic aggregated locally so number of channels can be reduced, however this limits the number of simultaneous calls to the number of channels |
All channels connected to the virtual PBX allowing as many conversations as phones |
| Only available in ‘blocks’ of 30 channels per service |
Requires a sufficiently good internet connection |
| Needs an expensive local PBX |
Remote PBX is free |
| Require maintenance charges |
No maintenance charges |
| Hardware is immediately out of date |
No hardware, so never out of date |
| Limited range of services supported, adding features is very expensive |
Massive range of services supported Adding a feature is free |
| Geography defines which numbers are available and how they can be used |
The system is independent of geography. Phone calls can be transferred across the globe free. You can select local geographic numbers for anywhere in the |
Conclusion
There may be a place for ISDN where there are a large number of phones, which are rarely used, but in all other circumstances hosted VoIP is the more powerful and cost effective solution. Cloud Net is unique in providing all of the hardware free with very low call costs.
Written by David Hill, Chairman, Cloud Net