Concurrent calls describes how many phone conversations an AI assistant can handle in parallel. It is the variable that decides whether a deployment survives a spike: a marketing campaign, an after-hours surge, Monday morning at a medical practice.
The limit is typically plan- or infrastructure-bound. Cloud vendors scale elastically; on-prem or hybrid setups hit ceilings faster. What matters operationally: is the limit soft (queueing) or hard (busy tone)?
Sound capacity planning derives from historical call patterns — average call duration × peak call rate yields required concurrency, with a 30 % safety margin as a baseline. Teams that cannot measure this should pick a vendor with a contractually guaranteed scale-out path.