Digital telephony /
Bellamy, John.
Digital telephony / John Bellamy. - 2nd ed. - New York : John Wiley & Sons, 1991. - xix, 572 p. : ill. ; 25 cm.
0471620564
Digital telephone systems.
Digital telephony / John Bellamy. - 2nd ed. - New York : John Wiley & Sons, 1991. - xix, 572 p. : ill. ; 25 cm.
0471620564
Digital telephone systems.
