Olympus TP-8 Telephone Pickup.

Ideal for any phone conversations: When speaking on the telephone, the TP-8 will capture both sides of the conversation for recording by your voice recorder. Just plug the TP-8 jack into the "MIC" jack of your recorder, and put the earphone side into your ear. The TP-8 is recommended for both cellular phones and landline phones including DECT standards.