Carriers are starting to move away from ISDN in favor of SIP. BT in the UK has announced it plans to migrate all ISDN customers on to the IP network by 2025. US telecoms provider, Verizon, stopped offering ISDN to new customers in May 2013. Logic would class this as sensible; cost savings all round, full scalability and enabling organisations to accommodate the increased use of smartphones (see July Blog – "Smartphones taking over as contact device of choice").
Contact centers reliant on ISDN know that moving and adding agents can be painful and expensive. New phone lines may be needed which can increase the number of ISDN channels required and trigger an order for another expensive ISDN trunk than can take weeks to be provisioned. Once installed, the extra ISDN trunk may not be fully utilised and you've had to commit to a lengthy contract. Not so with SIP. New agents can be set up instantly, being dynamically added to simply start using the bandwidth available. Likewise, variable workloads and seasonal variations are easily handled by SIP.
Some may consider SIP still vulnerable from the security point of view. Attempted DoS attacks and phreaks searching for ways to make free calls are common place. However, don't be alarmed; firewalls, fraud monitoring and session border controllers will take care of these points along with the ability to handle quickly and securely large volumes of SIP traffic.
Of course, a major decision that needs to be made regarding SIP affects organisations that have an in-house PBX. Successful deployment to a carrier hosted IP PBX will bring many benefits such as; completely eliminating capital cost for SIP infrastructure and reducing staffing overheads associated with the internal telecoms. Enjoy proper audit and tracking of all business conversations as normal practise with a hosted IP PBX, along with the accessible voicemail which is no longer siloed. Further, responsibility for the provisioning and secure communication clearly sits with the carrier thereby removing this headache from the organisation. Add to this the feature rich functionality provided by the IP PBX and the flexibility of being able to accommodate various endpoint types such as; mobile, softphone, pc headset and SIP phone, and the in-house PBX pales in comparison.
Your move from ISDN to SIP may come round faster than you expect. But, trust us - if you get it right and select your carrier not just on the basis of price but also on their managed infrastructure that lets you focus on your core business activity, you will wish it had happened sooner.