A thread on an #electronics problem, relating to transmitter contention on a RS-485 bus.
1/
I've been working a lot lately with a system based on an RS-485 bus, with multiple nodes on it. The bus talks async serial at 115.2kBaud, in short bursts of self-contained packets. Each packet has checksumming and sequence numbering, with a protocol of timeouts and retransmissions built on top of it for reliability.
Paul Evans
npub1hl…rgkyk
2025-08-18 17:16:03 UTC
Author Public Key
npub1hlpkkqf7sthaqvhufu9v2k8p0tpy5vcv8df6zaw4jzm36s3x3g7srrgkykSeen on
wss://relay.momostr.pinkPublished at
2025-08-18 17:16:03 UTCEvent JSON
{
"id": "d6ff0f077341a8947d9f15484e0c4bf338abb5bba77834698cbc541e01b0d3ac",
"pubkey": "bfc36b013e82efd032fc4f0ac558e17ac24a330c3b53a175d590b71d42268a3d",
"created_at": 1755537363,
"kind": 1,
"tags": [
[
"t",
"electronics"
],
[
"proxy",
"https://fosstodon.org/@leonerd/115050896670152576",
"web"
],
[
"proxy",
"https://fosstodon.org/users/leonerd/statuses/115050896670152576",
"activitypub"
],
[
"L",
"pink.momostr"
],
[
"l",
"pink.momostr.activitypub:https://fosstodon.org/users/leonerd/statuses/115050896670152576",
"pink.momostr"
],
[
"-"
]
],
"content": "A thread on an #electronics problem, relating to transmitter contention on a RS-485 bus.\n\n1/\nI've been working a lot lately with a system based on an RS-485 bus, with multiple nodes on it. The bus talks async serial at 115.2kBaud, in short bursts of self-contained packets. Each packet has checksumming and sequence numbering, with a protocol of timeouts and retransmissions built on top of it for reliability.",
"sig": "56b920c9cce29de8c424fde37df26b7641a8ec28726cab987aa78fb7a1e40c26957dbcb784361cda8059b8cc130f3eb9442bebfdef9f1fc41c90914918b15098"
}