Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Andrew Smallshaw Newsgroups: sci.electronics.repair Subject: Re: Re (2): USB functionality. Date: Tue, 19 Mar 2024 17:59:20 -0000 (UTC) Organization: A noiseless patient Spider Lines: 27 Message-ID: References: <2219572717.2fe80b82@uninhabited.net> <6449818651.785da3d8@uninhabited.net> <7189229973.1478ea1b@uninhabited.net> Injection-Date: Tue, 19 Mar 2024 17:59:20 -0000 (UTC) Injection-Info: dont-email.me; posting-host="52f5f3757a20b1d9f9bc57e10edabf0b"; logging-data="1013428"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19JFav6Z4zCReP4rjZdXM58GSgGNZdepSI=" User-Agent: slrn/1.0.3 (Patched for libcanlock3) (NetBSD) Cancel-Lock: sha1:3pLiWRc3AFBuON+zhyJjGi+i2Zg= Bytes: 2099 On 2024-03-13, Dan Purgert wrote: > On 2024-03-12, Roger Hayter wrote: >> On 12 Mar 2024 at 19:27:04 GMT, "Dan Purgert" wrote: >>> >>> There's only one set of pins (well, two sets if you count USB2 / USB3 -- >>> but you can only use one set at a time). >>> >>> USB2 -> D+/D- (Bi-directional / Half Duplex) >>> USB3 -> TX1+/TX1- and RX2+/RX2- (optionally Full Duplex, IIRC) >>> >>> As I recall the "Tx" pair is "Host Transmit to Peripheral", and "Rx" is >>> "Host Receive from Peripheral", but it's been a while since I read up on >>> the USB3 / USB-C implementations. >> >> Usbc seems to have about 20 pins, that's why I asked. > > Yeah, that's just to allow the connector to be flipped over, and still > connect to the host / peripheral. The host/peripheral ports themselves > only have one orientation. USB-C supports SuperSpeed which uses two additional pairs on top of USB2 and also allows for full-duplex. That is what the additional contacts on a USB3 A plug are for. -- Andrew Smallshaw andrews@sdf.org