Open Source Access Control Messaging Standard
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Draft Messaging Standard for Open Source Access Control
Low-level Signaling
Message format should be adaptable to the following mediums
- Serial
- RS-485
- Up to 32 devices per chain
- 9600-57600BPS
- Half-Duplex
- RS-232
- RS-485
- Ethernet
- REST style API(http POST/GET API)
- SMS/Cellular
- <140 characters or less per message
Desired Features
- Polling, and unique identification of nodes in the system
- Collision-handling and/or retry protocol
- CRC protocol for message integrity
- Encrypted/authenticated and cleartext messagig support
- Ability to interoperate if other protocols are on the same bus
- Can ignore messages in wrong format
- Graceful recovery/retry of messages
- Ethernet-style back-off in case of collisions?
- Need s rich library of polling, sending and control messages
Existing Protocols
<source lang="C">
//Copyright Royce Pipkins 2010 //May be used under the terms of the GPL V3 or higher. http://www.gnu.org/licenses/gpl.html /*
- ASCIIProtocol.h
- Created on: Mar 28, 2010
- Author: Royce Pipkins
- ASCII protocol driver
- Address and Type will be encoded as ascii-hex in the
- first four bytes after STX. The body string will follow
- as-is and will include the zero terminator. The next
- four bytes will be the 16 bit check sum of the everything
- past the STX up to the checksum expressed as ascii-hex
- [STX][ADDRESS][TYPE][BODYSTR][\0][CHECKSUM][ETX]
- The body string mustn't contain an STX or ETX or the receiver
- will reject the packet.
- /
</source>