The Full Stack Bill: Dialer License + SIP Trunk + Caller ID Together

Three Vendors, Three Billing Cycles, One Surprise

A fully operational outbound call center requires at minimum three services that are almost never bundled: a dialer (the software that paces and routes calls), a SIP trunk (the carrier that terminates those calls to the PSTN), and caller ID infrastructure (the phone numbers that appear on recipient screens). Each of these is sold by a different class of vendor with different pricing models, different contract terms, and different ways of measuring usage.

When you add them up, the combined invoice for a 20-agent floor typically lands between $3,400 and $7,200 per month depending on vendor tier and call volume. The wide range is exactly the problem.

The Dialer License

Dialer software is priced in one of three ways: per concurrent channel, per agent seat, or as a flat platform fee. Per-channel pricing is the most punishing for teams that run high dial ratios.

Cloud dialers at the $149 tier typically include predictive pacing, AMD, call recording, and basic reporting. They almost never include the SIP trunk or the phone numbers. Those are extra.

UnlimCall's Dialer add-on is priced at $79–$169 per seat per month depending on mode—power/preview at the low end, full predictive at the high end. It is layered on top of the voice seat, not a separate vendor relationship.

The SIP Trunk

SIP trunking is sold per-channel (concurrent call capacity) or per-minute. For a 20-agent predictive dialing floor running a 2.5:1 dial ratio, you need roughly 50 simultaneous channels at peak. That is 50 SIP channels, not 20.

The flat-rate model costs more than budget carriers at low volume. It costs less—or the same—once agents push past 200 connection-minutes per day. And it is the only model where a productive team does not generate a larger invoice than a slow team.

Caller ID Infrastructure

This is the most consistently underestimated cost in the stack. Local presence dialing—showing a number local to the recipient's area code—requires either a pool of DIDs you rent monthly or a vendor who provides on-demand caller ID routing.

Traditional DID pool for a 20-agent US domestic team covering 50 area codes:

A team calling across five countries with local presence in each needs 25+ international DIDs. At $3/DID/month that is $75/month just for international caller ID numbers, on top of the domestic pool. Over a year that is $900 in number rental that produces zero calls.

UnlimCall provides caller ID on demand across 33 live markets. There is no pre-purchased pool. You do not rent numbers in advance; the network routes caller ID to match the destination market at call time. The cost is zero incremental—it is part of the seat.

Where Redundancy Hides in the Three-Vendor Stack

When dialer, trunk, and caller ID come from separate vendors, you pay for integration overhead that does not appear on any invoice:

• Troubleshooting dead time: a call quality issue requires debugging across three vendor support queues before anyone claims responsibility.
• Over-provisioning SIP channels: because the dialer vendor and the trunk vendor bill separately, teams provision more channels than they use to avoid chokepoints—paying for idle capacity.
• DID number hygiene: numbers flagged as spam must be retired and replaced. With a static pool, that means ordering new DIDs, paying setup fees, and waiting for provisioning. The cost of spam-flagged numbers is a recurring operational tax that most teams budget inconsistently.

Sample 20-Seat Stack Comparison

The flat-rate model saves approximately $571 per month for this configuration. The saving grows with volume and with international call mix.