E

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 (B_e), PVCs and, 304

expansion. See growth

expectations, importance of reasonable, 333