Good Technical References:

Bates, Bud; Gregory, Donald
Voice and Data Communications Handbook
ISBN 0-07-005147-X (h), 1996

Black, Uyless D.
Physical Layer Interfaces and Protocols
ISBN 0-8186-5697-2
Second Edition - 1996

Chappell, Laura ed.
Advanced Cisco Router Configuration
ISBN 1-57870-074-4, 1999

Halabi, Bassam
Internet Routing Architectures
ISBN 1-56205-652-2, 1997

Held, Gilbert
Understanding Data Communications
6th ed. ISBN 0-7357-0036-2, 1999

Horak, Ray
Communications Systems and Networks
ISBN 1-55851-485-6 1st ed., 1997

Lewis, Christopher S.
Cisco TCP/IP Routing Professional Reference
ISBN 0-07-041088-7, 1998

Naugle, Matthew G.
Network Protocol Handbook
ISBN 0-07-046461-8, 1994

Potts, William F.
McGraw-Hill Data Communications Dictionary
ISBN 0-07-003154-1, 1993

Schrader, Robert L.
Electronic Communication 3rd Edition
ISBN 0-07-057138-4, 1975

Armstrong Jr., James C.
UNIX SECRETS
ISBN 1-56884-499-9, 1996

Hunt, Craig
TCP/IP Network Administration
ISBN 0-937175-82-X, 1992

Nemeth,Evi  ... (et al.)
UNIX System Administration Handbook
ISBN 0-13-151051-7 2nd ed., 1995