(a) A customer installation can have both DDI (Quota) and non-DDI channels (non Quota). Once a channel has been initially provided it can be changed from a DDI channel (Quota) to a non-DDI (non Quota) channel by reconfiguration of the channel which may involve a change in access rentals.

(b) For supply of new installations from 1 January 1997, the minimum number of channels permissible at an installation will be 8. Fewer channels will be provided if full connection and rental charges are paid for 8 channels. This does not apply to existing installations which can continue to pay for a minimum of 6 channels or for orders signed prior to 2 December 1996, which will be provided by 1 March 1997. The minimum number of channels required in order to qualify for the reduced connection charge for use of existing 2MB digital BT line plant is 15 channels for which connection charges and rentals will apply to the full 15 channel group.

(c) The diverted part of the call is charged to the renter of the service at standard dialled rates; calling customers pay the call charge only to the number dialled.

(d) These Barring Options are available; all calls, national and international calls, international calls only, operator calls and supplementary services.

(e) The minimum period of service is 12 months.

(f) Where permanent Outgoing or Incoming Call Barring on ISDN30/30e is requested at the same time as service is first provided at a customer site, then set up charges are included within the ISDN30 connection charges applicable to the first 15 channels at the site. Otherwise reconfiguration charges apply.

(h) Where a customer requests a previously unplanned addition to an existing ISDN 30 DDI installation the 'Changes to Numbers at an installation' charge applies plus any additional number charges which apply. This does not apply to directory numbers (SNDDI for ISDN30e) when provided at the time of initial installation.

(i) DDI rental charges apply to all numbers within the ranges provided.

(j) This service is not available at all exchanges. If a customer requests the service on an exchange not equipped for DDI, the appropriate Out-of-Area exchange line tariffs apply in addition to the standard DDI rates.

(k) Please note for new quota supply the full allocation of 10 DDI numbers per channel must be taken. Customers who require less than the full allocation must reduce the amount of quota channels and top up with the individual DDI.

(l) ISDN 30 (I.421) will not be available for new installations as from 25 January 1999. ISDN30 I421 has been withdrawn from new supply with effect from 10 April 2006.

(n) At multi tenanted buildings each customer will be viewed as new premises and the fact that 2Mb line plant is to the building does not entitle them to reduced charges.

(o) Same day transfer takes place when a customer takes over service ata site where it already exists (no new external wiring is provided) and there is no break in service. This must take place on the same calendar day.

(p) Non-same day transfer occurs when a customer takes over service at a site where it already exists (no new external wiring is provided) and there is a break in service and/or when the transfer occurs on different calendar days.

(q) Presentation Number (PN) is available to Business customers only. It is charged on a per Installation basis with one PN being allowed per Installation. These can only be ordered via the Presentation Number Service Centre, using the PN order form, which has to be signed by an authorised representative of the company requesting the service. The form, available from BT web sites, requires that the customer complies with legal requirements embodied in the Ofcom Code of Practice concerning the ownership and ability of the requested PN to receive calls. A PN must not be a number that connects to a revenue sharing number that generates an excessive or unexpected call charge. (NB the exploitation of a Presentation Number to generate revenue-sharing calls may constitute persistent misuse of an Electronic Communications Service and may result in the withdrawal of the service)

(r) A single installation means the ISDN 30 channels are terminated in the same location and the installation must have the same protocol (30e, DASS or I.421). Where a customer has DASS & 30e, this would be treated as separate installations. The ISDN 30 channels must be for a single customer only. At multi-tenanted sites each customers ISDN 30 will be treated as a separate installation.

(s) Multi line ISDN Anonymous Call Rejection (ACR) is available to Business customers only. It is charged on a per Installation basis with one ACR being allowed per Installation. A survey has to be completed to determine the provision date.

(t) Not available for new supply.