In API mode, each packet interval minimum is a number?

XBee Series2 serial port at 115200 baud

In API mode with the serial port to send every packet of data of the time interval between the minimum can reach a number time. Have a safe value? For example: time interval must be at least 10ms. This interval of time is used to find the network address and route?

Not sure your question, but in APi mode you should be able to literally send all packets end-to-end with no delay. However, eventually you may fill buffers & have data discarded.

So you cannot just send data at some time rate & hope you do not over-run the system. For exampe, if the remote node is a sleepign end-devcie with a poll-rate of 100msec, it will take up to 100 msec for it to detect that a packet is waiting to be fetched.

So ideally you send 1 frame, and watch for the correct ‘return’ meaning either a local response or a TX_Status response indicating the data was sent to another unit. Then I’d estimate a safe value is 3 active API frames.

I tried three nodes, a coordinator the other two are routers(router A and router B).
A router through A serial port are connected to the CPU, the router B connected to the PC. Using ND command can see networking success.
Let routers A send API data to the routing B, through the XCTU monitoring B received data. I found that only let CPU separation two frame data interval 10 milliseconds, in XCTU monitoring in the data is not lost bag.

The router will not sleep.
Interval at least 10 milliseconds can be receiving no packet loss.This value is normal? Or is there any other problems?
Thank you

There is no interval minimum which can promise no packet loss. As mentioned in other threads, ‘route discovery’ can consum up to 5000 msec, during which time none of your data is moving. If you keep sending packets into the XBee eventually it will start discarding them when the buffers are full - although you should see TX_STATUS errors returned for those.

If you really need to make data every 10 msec (or 50 or 100), then you need to use 802.15.4 without mesh support.