echo cancellers, function of, 224
echoes, identifying, 224
Edge Proxy Server (EPS), selecting for VoIP service, 318
800 numbers. See toll-free numbers
E&M protocols, 138–139
e-mail, data transfer using, 296–297
employees
analyzing phone lines per, 24
selecting Centrex/Centranet systems and, 28
E-1 circuit, 56
equipment. See hardware
erred seconds, 264
escalation list, using, 340
Ethereal software
overview, 313
troubleshooting VoIP with, 312
etiquette, troubleshooting, 212
excess burst size (Be), PVCs and, 304
expansion. See growth
expectations, importance of reasonable, 333