Can BTLE communication happen without service discovery?

Question

Hi,
We have nRF51822 acting as a central and another nRF51822 acting as peripheral. The peripheral advertises at 1 second advertisement interval. The peripheral and central have connection intervals as 7.5msec (minimum) and 20msec (maximum). The idea is the peripheral would be advertising for 12 hours. When a button is pressed in the central, the central would start to scan, find the correct peripheral (uuid match), connect to it, exchange a few security information and then disconnect. We wanted the whole interaction to be as quick as possible. When we broke down the steps, we found that 
 
 
 the services discovery (after establishing a connection) takes around 1 to 1.5 seconds. Is this usual? We have 2 primary services (doesnt have any characteristics) and 1 unknown service. There are 2 characteristics under the unknown service. 
 
 
 Is it possible to exchange information without doing a service discovery? Both the central and the peripheral know the uuid to write to and read from. If so, do you have any examples that does this? 
 
 
 Thanks.

Hung Bui · Accepted Answer

We need a sniffer trace to see what exactly happens and why it takes 1.5s 
 
 
 Yes, it's possible, but you need to know the characteristic handle values, not the UUID. You can find those handle values after service discovery and then can hardcode it in your application. You can also use nRF Connect (on PC) to find the handle values.