Just what the title says. And what effect will putting 0 in that box have? I'm able to make and take outbound and inbound calls respectively with the limit set to 0.

Hi Logos, To manage call concurrency effectively, every Vapi account starts with 10 concurrent call slots by default. This means you can handle up to 10 calls simultaneously before others are queued. To increase your concurrency limit: 1. Open the [Vapi Dashboard](https://dashboard.vapi.ai/settings/billing). 2. Navigate to Settings → Billing. 3. Under Reserved Concurrency (Call Lines), adjust the limit or buy additional concurrency lines. For larger outbound campaigns, consider breaking down lead lists into smaller batches to stay within limits. If your monthly usage regularly exceeds 50,000 minutes, explore custom plans or add-on bundles for more capacity. To monitor concurrency usage and avoid hitting caps, utilize the API responses and Analytics API, which provide detailed insights into current and historical call usage patterns. You can also set up alerts to notify you when you're nearing your limit. For more information, refer to [Understanding Call Concurrency](https://docs.vapi.ai/calls/call-concurrency).