Carrier Pre-Selection (CPS) allows you to choose which telecommunications provider you want to carry your voice calls. There is no inconvenience involved with CPS, no autodiallers, manual prefixing or PBX reprogramming; you keep your existing phone numbers and continue to make calls as usual.

Carrier Pre-Selection uses network access technology, so traffic originating from your site will be routed directly to your chosen network with no need for prefix codes. The "selection" of the preferred provider is done automatically at point of entry (the local exchange) to the public voice network.

Certain types of call are not carried via CPS as they are BT services and included in the rental charges. These include calls to emergency numbers, operator assistance, directory enquiries and number ranges used for flat rate Internet access (those starting with 0844 04 or 0808 99). You will continue to have access to these services and any charges will appear on your BT bill.

BT will still own, run and bill for the physical phone line. Your phone number will remain the same and you will simply receive a separate bill from Westlake instead of BT (for calls).