Latency with Ademco Vista128 + AlarmDecoder binding?

Looking for data, either anecdotal or actual measurements, on the latency and response time of sensors in the following configuration:

Hard-wired door closure contact --> Honeywell Vista128 alarm system --> AlarmDecoder rs232 serial device --> OpenHAB server.

Assume all items are optimized and the OpenHAB server is running on a dedicated fast computer, i.e Intel Core i5 / 4GB Ram / SSD on SATA bus.

When a contact changes state from open to closed, how long is it before the OpenHAB server sees the state change? 10 milliseconds? 100ms? 250ms or more?

Thanks for your detailed replies.

Predictable and bounded latencies are not an openhab feature. I would guess median to be 1sec.