delta CRL: A document that lists certificates that have been revoked after the last full certificate revocation list (CRL) has been published. Delta CRLs are maintained and published by a certification authority (CA), and they are normally much smaller than a full CRL.
Service Profile Identifier (SPID): An 8-digit to 14-digit number that identifies the services that you order for each B-channel. For example, when you order Primary Rate ISDN, you obtain two phone numbers and two SPIDs from your Integrated Services Digital Network (ISDN) provider. Typical ISDN adapters cannot operate without configuring SPIDs.