GATT Characteristic Read Timeout

Question

Hello, 
 i can't find the characteristic read timeout in BLE Core SPEC 4.0. If the central device read a characteristic from the peripheral device, in which time the peripheral device must answer? 
 In the Bluetooth Core Spec i just find in Volumen 3 - Core System Package --> Part G (GATT) --> 4.14 Procedure Timeouts. Here, however, no exact time is described.

Ulrich Myhre · Accepted Answer

It is defined as 30 seconds in the spec. See Vol 3 (Host) - Part F (ATT) - 3.3.3 (Transaction). 
 "A transaction not completed within 30 seconds shall time out. Such a transaction shall be considered to have failed and the local higher layers shall be informed of this failure. No more attribute protocol requests, commands, indications or notifications shall be sent to the target device on this ATT Bearer." 
 GATT is an extension built on top of ATT, so it should also adhere to this rule. In general, most of the timeouts in BLE seem to be 30 seconds - with the notable exception of link-layer procedures that are tied to a 60 seconds RX timeout.

GATT Characteristic Read Timeout

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