In-Span Interconnect (ISI) provides you with the ability to offer PSTN (Public Switch Telephone Network) telephony and data services to your customers, by providing the physical access and 2Mbit/s connection to a BT exchange. You can then benefit from Call Origination and Call Termination on BTs PSTN network.
ISI provides interconnection using either Plesiochronous Digital Hierarchy (PDH) or Synchronous Digital Hierarchy (SDH) transmission technologies, assuring high service availability and resilience. Furthermore it offers national coverage and access to BT interconnect and transit call charges.
Operational costs are kept low as infrastructure is built collaboratively. Equipment is installed by yourself in on your premises, which interconnects at an agreed Point of Connection (PoC) in the public highway. Therefore you require the necessary permits and expertise to work in the public highway.
If the PoC is within 100m of the BT building no charges apply. If however you wish to nominate an alternative PoC, separate charges are applicable. This option is called Nominated ISI.
From the PoC you have the ability to extend the reach of your network to remote BT switches via 2Mbit/s Interconnect Extension Circuits (IECs), thus minimising further capital outlay.
To complete an ISI interconnection, 2Mbit/s Intra-Building Circuits (IBCs) are required at the BT exchange. This provides connectivity from the ISI equipment to the BT switch. Separate charges will apply for the IBC.
Customer Sited Interconnect (CSI) is an alternative option to ISI
