411 REFERENCE · Wikibooks
CCNA Certification/Appendix E - Material removed from course
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
As of this writing (May 2, 2008), it appears that in Cisco's most recent revision to the CCNA exam coverage, they have removed the requirement for the candidate to have extensive knowledge of ISDN.