PBX systems for IP telephony
Sulkin, Allan
PBX systems for IP telephony - New York McGraw Hill 2002 - viii, 487 p. : ill. ; 24 cm - McGraw-Hill telecom professional .
Includes index
0071375686
PBX systems for IP telephony - New York McGraw Hill 2002 - viii, 487 p. : ill. ; 24 cm - McGraw-Hill telecom professional .
Includes index
0071375686