The period is based on the calendar year, starting in January. The DVD is despatched at the end of each quarter.

4 quarterly updates (covering the all year): one edition of the ETSI EDS DVD-ROM per quarter until the end of the year and access to the EDS On-line Update service during the subscription period.
1 quarterly update: one time shipment of the quarterly update DVD, this order does NOT include access to the EDS On-line Update service.
Additional copies: to be able to order an additional copy you have to order a Quarterly update.
For your information, the ETSI Documentation Service (EDS) contains:

• full text versions of all ETSI standards (including 3GPP): ENs, TSs, TRs, ESs, SRs, EGs, ETSs, TBRs, GSM TSs, ETRs, NETs, etc.;
• all editions of published deliverables;
• all drafts currently under various approval procedures;
• full-text search and a complete list of deliverables matching the search, and
• integrated HELP and keyword searching.