Receptor: 1. In cell biology, a structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance. There are many receptors.
The most common is EPNS (Electro Plated Nickel Silver) but many other symbols are used: 1  EPBM (Electro Plated Britannia Metal). 2  EPCA (Electro Plated Copper Alloy). 3  ESM (Electro Plated Silver Mounts).he most common is EPNS (Electro Plated Nickel Silver) but many other symbols are used: 1  EPBM (Electro Plated Britannia Metal). 2  EPCA (Electro Plated Copper Alloy). 3  ESM (Electro Plated Silver Mounts).
PSTN Definition The public switched telephone network (PSTN) is the worldwide collection of interconnected public telephone networks that was designed primarily for voice traffic. The PSTN is a circuit-switched network. That is, a dedicated circuit (also referred to as a channel) is established for the duration of a transmission, such as a telephone call.