Your Dialer Is Only as Good
as the Trunk Feeding It.

Predictive dialers generate burst traffic — 200 to 500 concurrent SIP sessions that fluctuate every few seconds based on answer rate changes. Carriers with channel caps throttle the dialer's algorithm. Carriers with high PDD break the pacing predictions. Carriers with B-level attestation reduce answer rates by 10 to 20 percent. A carrier built for predictive dialing eliminates all three problems: unlimited channels, low PDD, and A-level attestation.

Agents × dial ratio = concurrent channels. 50 agents at 4:1 ratio = 200 channels. Add 25 percent for burst headroom: 250 channels. On SIPNEX, this is not a number you purchase — channels are unlimited. Your capacity is your bandwidth (100 kbps per G.711 call) and your server resources.

Yes, significantly. A-level attestation (direct carrier verification) versus B-level (reseller inherited) typically represents a 10 to 20 percent answer rate difference on the same leads. On 100,000 calls per month, that is 10,000 to 20,000 additional live conversations. SIPNEX signs every call with our own SP-KI certificate at A-level.

G.711u (ulaw) is the standard. It provides the highest audio quality and the best AMD (Answering Machine Detection) accuracy. AMD algorithms are tuned for uncompressed waveforms — G.729 compression increases false positive rates. Each G.711 call uses approximately 85 kbps. See our codec comparison guide.

SIPNEX targets sub-3-second PDD for US domestic outbound. High or variable PDD breaks predictive dialing algorithms — the pacing predictions assume consistent call setup times. If PDD varies from 2 to 8 seconds across calls, the dialer over-dials on some cycles and under-dials on others, increasing abandon rates and idle time.

Yes. SIPNEX was built by VICIdial operators. Our support team runs VICIdial on our own network. We provide sip.conf recommendations, codec tuning for AMD, CID rotation strategy, and troubleshooting from engineers who have configured the same system. See our VICIdial carrier page for details.

Per-minute wholesale rates from $0.005 to $0.030 depending on volume and destination. No per-channel fees. No platform fees. No setup fees. 6-second billing. Published rates on our pricing page. A 50-agent operation running 500,000 minutes per month typically pays $2,500 to $6,000 — significantly less than CPaaS alternatives like Twilio.

Yes. SIPNEX provisions trunks in 24 hours with no long-term commitment. Run a test campaign alongside your current carrier and compare answer rates, PDD, audio quality, and total cost. No minimum term. No early termination penalty.