RS-485 is an electrical signaling standard, for carrying arbitrary bytes between a transmitter and a receiver. There isn't even any built-in concept of a packet, let alone an addressing scheme. It's no different than RS-232 at all, in that respect.
When compared against RS-232, only the signaling voltage and impedance requirements are different. That, and also RS-485 has no standardized connectors or side-band signals (like CTS/RTS).
Sometimes RS-485 is used half-duplex over a shared differential pair. In situations like that, slave devices are often designed to keep their transmitters disabled unless responding. Sometimes, these setups will have a couple of devices listening for data.
Lots of people implement custom bus protocols _over_ RS-485. But RS-485 by itself has no concept of buses, packets, addressing, channels, slave devices, or master devices. It's just an electrical signaling standard. Nothing more, nothing less.
It's kind of like saying "AM radio-waves are a format for carrying music". Sure, some people transmit music over AM radio. But that doesn't mean that the actual radio waves have any knowledge or accommodation for what they're carrying.
RS-485 is an electrical signaling standard, for carrying arbitrary bytes between a transmitter and a receiver. There isn't even any built-in concept of a packet, let alone an addressing scheme. It's no different than RS-232 at all, in that respect.
When compared against RS-232, only the signaling voltage and impedance requirements are different. That, and also RS-485 has no standardized connectors or side-band signals (like CTS/RTS).
Sometimes RS-485 is used half-duplex over a shared differential pair. In situations like that, slave devices are often designed to keep their transmitters disabled unless responding. Sometimes, these setups will have a couple of devices listening for data.
Lots of people implement custom bus protocols _over_ RS-485. But RS-485 by itself has no concept of buses, packets, addressing, channels, slave devices, or master devices. It's just an electrical signaling standard. Nothing more, nothing less.
It's kind of like saying "AM radio-waves are a format for carrying music". Sure, some people transmit music over AM radio. But that doesn't mean that the actual radio waves have any knowledge or accommodation for what they're carrying.