Application note from Vishay on their VSOP98260 IR learning chip which uses the same IR LED as transceiver. Link here (PDF)
There is a wide interest in universal remote controls, which can be used to diminish the “clutter” of remote controls typically present in a modern living room setting. Training the universal remote to send the correct code to each of possibly many appliances in any media setting is not a simple task.
Infrared remote controls transmit their signals via an infrared LED. The simplest and least expensive code learning technique devised to date uses this same infrared LED as both the code transmitter and the code detector for receiving signals from the appliance remote. IR LEDs are not very efficient detectors. Fortunately, for code learning we want to use an inefficient detector to eliminate any spurious signals present in the room. The much stronger signal from the appliance remote, which is held close to the detector, will be enough to capture a clean signal.