Rick C <gnuarm.deletethisbit@gmail.com> wrote:> On Thursday, January 19, 2023 at 5:29:44 AM UTC-5, Theo wrote: > > Paul Rubin <no.e...@nospam.invalid> wrote: > > > Theo <theom...@chiark.greenend.org.uk> writes: > > > > Another thought is to find a common 'gender changer' case, a plastic case > > > > that would take a DB9 connector at each end, and drop in your own PCB. eg > > > > > > I think the hope is to not build hardware at all, including dropping > > > boards into things, but instead to buy a complete and packaged box that > > > you can plug cables into. I'm surprised that it seems this difficult. > > > Maybe it is an opportunity. > > I know, but I don't think there are better options. > > > > I'm not really surprised, because the existence of a piece of hardware > > depends on a pre-existing market for that hardware. The market for > > RS232-to-X is well established, for various X. But RS232 to RS232 seems > > less likely, because it's not clear what people would use it for. > > You aren't making sense. There are literally hundreds if not thousands of > boxes with two serial ports. Some have only that. Others have extra > ports. But none are programmable. There are lots of programmable > controllers with dual serial ports, but not in an enclosure. Not sure > what you are trying to say. But it's not important, because it's not an > advancement toward a solution.You indicated you wanted RS232-to-RS232, with no extra stuff. Not hardwired, not a PC, not a pile of dongles plugged into another thing. Show me the boxes that do that. You can of course find boxes that happen to have two serial ports as well as (lots of) other stuff. But they're designed to do some other 'X' (eg Modbus), and aren't (officially) reprogrammable. What is the use case for a programmable RS232-to-RS232 product? If you can think of a use case, maybe you can find somebody who makes such a thing.> Alibaba is literally the last place I would by something like this, for > all the obvious reasons, including the risk of never seeing the product or > your money again.Alibaba is a good place to answer the question 'if you can think of it, does it exist?'. I would not buy them from there. But, for example, it turned up the dual RS232 to Modbus converters. Once knowing that as a possible market I might then go and see if there was a sensible supplier of that. Searching Alibaba did not come up with examples of boxes doing RS232 to RS232, which suggests that specifically is a market that doesn't really exist. A PLC is one starting point - maybe there's a dual RS232 PLC out there. Alibaba shows various RS232 PLCs - maybe something like that would suffice (from a local supplier)? Theo
Boxed MCU with RS-232 Port
Started by ●January 17, 2023
Reply by ●January 20, 20232023-01-20
Reply by ●January 20, 20232023-01-20
On Friday, January 20, 2023 at 8:03:30 AM UTC-5, Theo wrote:> Rick C <gnuarm.del...@gmail.com> wrote: > > On Thursday, January 19, 2023 at 5:29:44 AM UTC-5, Theo wrote: > > > Paul Rubin <no.e...@nospam.invalid> wrote: > > > > Theo <theom...@chiark.greenend.org.uk> writes: > > > > > Another thought is to find a common 'gender changer' case, a plastic case > > > > > that would take a DB9 connector at each end, and drop in your own PCB. eg > > > > > > > > I think the hope is to not build hardware at all, including dropping > > > > boards into things, but instead to buy a complete and packaged box that > > > > you can plug cables into. I'm surprised that it seems this difficult. > > > > Maybe it is an opportunity. > > > I know, but I don't think there are better options. > > > > > > I'm not really surprised, because the existence of a piece of hardware > > > depends on a pre-existing market for that hardware. The market for > > > RS232-to-X is well established, for various X. But RS232 to RS232 seems > > > less likely, because it's not clear what people would use it for. > > > > You aren't making sense. There are literally hundreds if not thousands of > > boxes with two serial ports. Some have only that. Others have extra > > ports. But none are programmable. There are lots of programmable > > controllers with dual serial ports, but not in an enclosure. Not sure > > what you are trying to say. But it's not important, because it's not an > > advancement toward a solution. > You indicated you wanted RS232-to-RS232, with no extra stuff. Not > hardwired, not a PC, not a pile of dongles plugged into another thing. > Show me the boxes that do that.I didn't say no "extra stuff". If it has other I/O, that's ok, just not excessive. A full blown PC has the problem that it is not easily rebooted, much larger than an MCU based device and sucks power. Here are some devices that would be perfectly suitable if they were programmable. https://www.brainboxes.com/product/usb-to-serial/usb/us-257 https://www.brainboxes.com/product/ethernet-to-serial/db9/es-257> You can of course find boxes that happen to have two serial ports as well as > (lots of) other stuff. But they're designed to do some other 'X' (eg > Modbus), and aren't (officially) reprogrammable.Yes, that's the problem.> What is the use case for a programmable RS232-to-RS232 product?Who cares? You seem just be interested in an argument. What's the use case for any programmable device? This application is a perfect example.> If you can think of a use case, maybe you can find somebody who makes such a > thing.If it has serial ports and is programmable, it would not be sold for a specific use case. The industrial computers or PLC devices are not sold for a specific use case.> > Alibaba is literally the last place I would by something like this, for > > all the obvious reasons, including the risk of never seeing the product or > > your money again. > Alibaba is a good place to answer the question 'if you can think of it, does > it exist?'. I would not buy them from there. But, for example, it turned > up the dual RS232 to Modbus converters. Once knowing that as a possible > market I might then go and see if there was a sensible supplier of that.Perhaps you could explain what Modbus is and how it is related to this? Would such a converter be programmable?> Searching Alibaba did not come up with examples of boxes doing RS232 to > RS232, which suggests that specifically is a market that doesn't really > exist.Still hung up on "markets", eh?> A PLC is one starting point - maybe there's a dual RS232 PLC out there. > Alibaba shows various RS232 PLCs - maybe something like that would suffice > (from a local supplier)?Perhaps, but I haven't found one with any RS232, other than as attached modules and that always raises the price far too much. Even the PLC is too expensive, being some hundreds of dollars, rather than the lower end price I'm looking for. Thanks for your comments. -- Rick C. --++ Get 1,000 miles of free Supercharging --++ Tesla referral code - https://ts.la/richard11209
Reply by ●January 20, 20232023-01-20
On 19.01.2023 19:06, Rick C wrote: > You aren't making sense. There are literally hundreds if not > thousands of boxes with two serial ports. Some have only that. > Others have extra ports. But none are programmable. There > are lots of programmable controllers with dual serial ports, > but not in an enclosure. Seems you are 25 years to late. But this company is still selling its device (with a Z180 processor). Seems this is what you are asking for (but maybe without the price): https://www.kksystems.com/programmable-protocol-converters/ppc-4-h2-c.html/ https://www.kksystems.com/datasheets/pdf_files/ppclft.pdf https://www.kksystems.com/datasheets/pdf_files/ppcman.pdf > Alibaba is literally the last place I would by something like > this, for all the obvious reasons, including the risk of never > Yseeing the product or your money again. I bought many things from Aliexpress an nearly never had any problems.
Reply by ●January 20, 20232023-01-20
On Friday, January 20, 2023 at 1:17:59 PM UTC-5, Herbert Kleebauer wrote:> On 19.01.2023 19:06, Rick C wrote: > > > > You aren't making sense. There are literally hundreds if not > > thousands of boxes with two serial ports. Some have only that. > > Others have extra ports. But none are programmable. There > > are lots of programmable controllers with dual serial ports, > > but not in an enclosure. > Seems you are 25 years to late. But this company is still selling > its device (with a Z180 processor). Seems this is what you are > asking for (but maybe without the price): > > https://www.kksystems.com/programmable-protocol-converters/ppc-4-h2-c.html/ > https://www.kksystems.com/datasheets/pdf_files/ppclft.pdf > https://www.kksystems.com/datasheets/pdf_files/ppcman.pdf > > Alibaba is literally the last place I would by something like > > this, for all the obvious reasons, including the risk of never > > Yseeing the product or your money again. > > I bought many things from Aliexpress an nearly never had > any problems.I'm pleased for you. People safely cross streets outside the crosswalk, yet people are killed doing that every day. Do you tell your kids it's a good thing to do? -- Rick C. -+-- Get 1,000 miles of free Supercharging -+-- Tesla referral code - https://ts.la/richard11209
Reply by ●January 20, 20232023-01-20
On 1/20/2023 22:37, Rick C wrote:> On Friday, January 20, 2023 at 1:17:59 PM UTC-5, Herbert Kleebauer wrote: >> On 19.01.2023 19:06, Rick C wrote: >> >> >>> You aren't making sense. There are literally hundreds if not >>> thousands of boxes with two serial ports. Some have only that. >>> Others have extra ports. But none are programmable. There >>> are lots of programmable controllers with dual serial ports, >>> but not in an enclosure. >> Seems you are 25 years to late. But this company is still selling >> its device (with a Z180 processor). Seems this is what you are >> asking for (but maybe without the price): >> >> https://www.kksystems.com/programmable-protocol-converters/ppc-4-h2-c.html/ >> https://www.kksystems.com/datasheets/pdf_files/ppclft.pdf >> https://www.kksystems.com/datasheets/pdf_files/ppcman.pdf >>> Alibaba is literally the last place I would by something like >>> this, for all the obvious reasons, including the risk of never >>> Yseeing the product or your money again. >> >> I bought many things from Aliexpress an nearly never had >> any problems. > > I'm pleased for you. People safely cross streets outside the crosswalk, yet people are killed doing that every day. Do you tell your kids it's a good thing to do? >Buying a $10 or a $100 thing at aliexpress is not that similar to getting killed, you know. I have bought a lot of small stuff there and have not yet been killed. Oh yes, and I do cross streets as I please and I am still alive, but that's not a very similar matter, as explained above.
Reply by ●January 20, 20232023-01-20
On Friday, January 20, 2023 at 4:02:27 PM UTC-5, Dimiter wrote:> On 1/20/2023 22:37, Rick C wrote: > > On Friday, January 20, 2023 at 1:17:59 PM UTC-5, Herbert Kleebauer wrote: > >> On 19.01.2023 19:06, Rick C wrote: > >> > >> > >>> You aren't making sense. There are literally hundreds if not > >>> thousands of boxes with two serial ports. Some have only that. > >>> Others have extra ports. But none are programmable. There > >>> are lots of programmable controllers with dual serial ports, > >>> but not in an enclosure. > >> Seems you are 25 years to late. But this company is still selling > >> its device (with a Z180 processor). Seems this is what you are > >> asking for (but maybe without the price): > >> > >> https://www.kksystems.com/programmable-protocol-converters/ppc-4-h2-c.html/ > >> https://www.kksystems.com/datasheets/pdf_files/ppclft.pdf > >> https://www.kksystems.com/datasheets/pdf_files/ppcman.pdf > >>> Alibaba is literally the last place I would by something like > >>> this, for all the obvious reasons, including the risk of never > >>> Yseeing the product or your money again. > >> > >> I bought many things from Aliexpress an nearly never had > >> any problems. > > > > I'm pleased for you. People safely cross streets outside the crosswalk, yet people are killed doing that every day. Do you tell your kids it's a good thing to do? > > > Buying a $10 or a $100 thing at aliexpress is not that similar > to getting killed, you know. > I have bought a lot of small stuff there and have not yet been killed. > Oh yes, and I do cross streets as I please and I am still alive, but > that's not a very similar matter, as explained above.My experience with Alibaba is not the same as yours. With Ebay, I can dispute a sale and get a refund. Alibaba spent literally months demanding more and more things from me, many which made no sense because of the language barrier. In the end, they said I failed to prove the vendor was lying when he said he shipped the item listed. Photos were not good enough. They wanted a video for some reason. Alibaba simply does not support their customers, so I don't use them. Ebay is worth while, but some things sold are perpetually fake, or crap and you have to buy them to find out, then make the "return", which the vendor is required to pay for, so they often say keep it. I even bought crap wire on Ebay from a vendor relatively local. The actual wire gauge was about three numbers below the claimed AWG. Bought 20 gauge and got 23 gauge. Bought 18 gauge and got 21 gauge, etc. I was getting the refund, so I thought I'd try seeing how far this went. 16 gauge was actually 19 gauge and 12 gauge, was actually 15 gauge. The vendor could not say they didn't know, the wire insulation has *their* name on it! So it's a custom marked product. How could they not know they are selling mislabeled wire? Yeah, they all sell crap. I just find it possible to get a refund from Ebay. Alibaba, not so much. -- Rick C. -+-+ Get 1,000 miles of free Supercharging -+-+ Tesla referral code - https://ts.la/richard11209
Reply by ●January 20, 20232023-01-20
On 1/21/2023 0:08, Rick C wrote:> On Friday, January 20, 2023 at 4:02:27 PM UTC-5, Dimiter wrote: >> On 1/20/2023 22:37, Rick C wrote: >>> On Friday, January 20, 2023 at 1:17:59 PM UTC-5, Herbert Kleebauer wrote: >>>> On 19.01.2023 19:06, Rick C wrote: >>>> >>>> >>>>> You aren't making sense. There are literally hundreds if not >>>>> thousands of boxes with two serial ports. Some have only that. >>>>> Others have extra ports. But none are programmable. There >>>>> are lots of programmable controllers with dual serial ports, >>>>> but not in an enclosure. >>>> Seems you are 25 years to late. But this company is still selling >>>> its device (with a Z180 processor). Seems this is what you are >>>> asking for (but maybe without the price): >>>> >>>> https://www.kksystems.com/programmable-protocol-converters/ppc-4-h2-c.html/ >>>> https://www.kksystems.com/datasheets/pdf_files/ppclft.pdf >>>> https://www.kksystems.com/datasheets/pdf_files/ppcman.pdf >>>>> Alibaba is literally the last place I would by something like >>>>> this, for all the obvious reasons, including the risk of never >>>>> Yseeing the product or your money again. >>>> >>>> I bought many things from Aliexpress an nearly never had >>>> any problems. >>> >>> I'm pleased for you. People safely cross streets outside the crosswalk, yet people are killed doing that every day. Do you tell your kids it's a good thing to do? >>> >> Buying a $10 or a $100 thing at aliexpress is not that similar >> to getting killed, you know. >> I have bought a lot of small stuff there and have not yet been killed. >> Oh yes, and I do cross streets as I please and I am still alive, but >> that's not a very similar matter, as explained above. > > My experience with Alibaba is not the same as yours. With Ebay, I can dispute a sale and get a refund. Alibaba spent literally months demanding more and more things from me, many which made no sense because of the language barrier. In the end, they said I failed to prove the vendor was lying when he said he shipped the item listed. Photos were not good enough. They wanted a video for some reason. Alibaba simply does not support their customers, so I don't use them. Ebay is worth while, but some things sold are perpetually fake, or crap and you have to buy them to find out, then make the "return", which the vendor is required to pay for, so they often say keep it. > > I even bought crap wire on Ebay from a vendor relatively local. The actual wire gauge was about three numbers below the claimed AWG. Bought 20 gauge and got 23 gauge. Bought 18 gauge and got 21 gauge, etc. I was getting the refund, so I thought I'd try seeing how far this went. 16 gauge was actually 19 gauge and 12 gauge, was actually 15 gauge. The vendor could not say they didn't know, the wire insulation has *their* name on it! So it's a custom marked product. How could they not know they are selling mislabeled wire? > > Yeah, they all sell crap. I just find it possible to get a refund from Ebay. Alibaba, not so much. >I am not sure I'd bother to open a $10 dispute on aliexpress, I'd expect your outcome plus wasted time. I can't remember buying anything which costs > $100. They try to keep their reputation (aliexpress, not alibaba) as they make their money on huge sale quantities of small value all over the planet. Recently I bought a nice keyboard at something like $40+, can't believe I got something *that* good at this price (way better than the Cherry-G84-s I have been using for decades now). On alibaba the risks are way higher I guess, depends on luck. My sister buys stuff from someone in Pakistan she found over alibaba and she is happy (many years now). No surprise your experience has been different. I would not consider buying chips on either alibaba or aliexpress of course. I bought some fast HV diodes on ebay twice and what I got was not just OK but unobtainable otherwise.... Go figure, life is colourful and full of risks of various probabilities and stakes.
Reply by ●January 20, 20232023-01-20
Rick C <gnuarm.deletethisbit@gmail.com> wrote:> On Friday, January 20, 2023 at 4:02:27 PM UTC-5, Dimiter wrote: > > On 1/20/2023 22:37, Rick C wrote: > > > On Friday, January 20, 2023 at 1:17:59 PM UTC-5, Herbert Kleebauer wrote: > > >> On 19.01.2023 19:06, Rick C wrote: > > >> > > >> > > >>> You aren't making sense. There are literally hundreds if not > > >>> thousands of boxes with two serial ports. Some have only that. > > >>> Others have extra ports. But none are programmable. There > > >>> are lots of programmable controllers with dual serial ports, > > >>> but not in an enclosure. > > >> Seems you are 25 years to late. But this company is still selling > > >> its device (with a Z180 processor). Seems this is what you are > > >> asking for (but maybe without the price): > > >> > > >> https://www.kksystems.com/programmable-protocol-converters/ppc-4-h2-c.html/ > > >> https://www.kksystems.com/datasheets/pdf_files/ppclft.pdf > > >> https://www.kksystems.com/datasheets/pdf_files/ppcman.pdf > > >>> Alibaba is literally the last place I would by something like > > >>> this, for all the obvious reasons, including the risk of never > > >>> Yseeing the product or your money again. > > >> > > >> I bought many things from Aliexpress an nearly never had > > >> any problems. > > > > > > I'm pleased for you. People safely cross streets outside the crosswalk, yet people are killed doing that every day. Do you tell your kids it's a good thing to do? > > > > > Buying a $10 or a $100 thing at aliexpress is not that similar > > to getting killed, you know. > > I have bought a lot of small stuff there and have not yet been killed. > > Oh yes, and I do cross streets as I please and I am still alive, but > > that's not a very similar matter, as explained above. > > My experience with Alibaba is not the same as yours. With Ebay, I can dispute a sale and get a refund. Alibaba spent literally months demanding more and more things from me, many which made no sense because of the language barrier. In the end, they said I failed to prove the vendor was lying when he said he shipped the item listed. Photos were not good enough. They wanted a video for some reason. Alibaba simply does not support their customers, so I don't use them. Ebay is worth while, but some things sold are perpetually fake, or crap and you have to buy them to find out, then make the "return", which the vendor is required to pay for, so they often say keep it. > > I even bought crap wire on Ebay from a vendor relatively local. The actual wire gauge was about three numbers below the claimed AWG. Bought 20 gauge and got 23 gauge. Bought 18 gauge and got 21 gauge, etc. I was getting the refund, so I thought I'd try seeing how far this went. 16 gauge was actually 19 gauge and 12 gauge, was actually 15 gauge. The vendor could not say they didn't know, the wire insulation has *their* name on it! So it's a custom marked product. How could they not know they are selling mislabeled wire? > > Yeah, they all sell crap. I just find it possible to get a refund from Ebay. Alibaba, not so much. >IIUC Alibaba is intended for larger transactions and has different rules than Aliexpress. I did only small or very small transactions. For me problem with Ebay was that with cheap shipping things would not arrive and there were no way to dispute this. I can understand this, without tracking there is no way to know who was to blame: seller, mail or fraudolent customer. Tracked shipping was significantly more expensive than goods that I wanted to buy. OTOH things with cheap/free shipping ordered on Aliexpress were arriving fine. So my conclusion was that Ebay sellers were at fault and I stopped buying on Ebay. There was period when also some shipments from Aliexpress vanished, but AFAICS Aliexpress got this under control: they have reasonably cheap tracked shipping and it seem that on all shipments they track if package leaves China. That probably removes all incentives for sellers to fail sending things. Most Aliexpress seller have resonably high volumes. They sell what customers want to buy. It can not be completely non functional, there are not enough fools to support this. The problem is that most customers are unable or unwillig to fully examine what they bought. So you get rechargable batteries with completely bogus stated capacity or USB chargers with inflated charging current. I bought a lot of things on Aliexpress but I am trying to keep realistic expectations. I bought few USB chargers knowing that stated current (2.1 A) is much bigger than real one (0.85 A), but they were good enough for my purpose. I bought resistors and small power transistors. My reasoning was that making something that looks like resistor or transistor in small/medium volume is probably more expensive than real resistor/transistor in high volume. And hopefully there are not enough fools to fund high volume manufacturing of fake transistors. Well, I got resistors and resonably performing transistors. I can not say if there are some hidden troubles but to the moment I am satisfied with what I bought. In the past I bought few STM chips from Chinese sellers. AFAIK those chips were widely used in China, the unit price was much lower than unit price from western distributors, but significantly higher that supposed volume price. So it looked resonable that Chinese seller could sell them at lower margin and still make a profit. And up to now I had no problem with those chips. OTOH if there is advanced/rare western part it would be strange if Chinese seller had some magic cheap source of the part, so I am very suspicious of such offers. Power mosfets were borderline case. Around 2019 I bought packs of 10 from several sellers. Essentially all were out of specs (too large Rds_on). If there were moderate discrepancy I made comments stating real paramenter, in few cases of really large discrepancy I requested partial refund (and got it possibly after a dispute). To say the truth, refunds that I got were probably not worth my time, I did this mostly from feeling of moral duty, to make sure sellers know that there is problem and to discourage them from selling such bad parts. When buying on Aliexpress it is useful to read buyers comments. Especially Russians tend to measure/test bought parts, so you can have resonable idea what you are buying. BTW: classic Arduino boards are supposed to have Atmega 328P. I have heard that recently a lot of boards instead had Chinese chip. IIUC such boards also appeared in western distribution channels, so it is possible that some Arduino boards that you use is equpped with Chinese chip. On paper Chinese chip should be better than Atmega 328P, but it has incompatiblities. For simple use in Arduino it may be compatible enough, but in case of troubles difference between chips is one of possible reasons. -- Waldek Hebisch
Reply by ●January 20, 20232023-01-20
On Friday, January 20, 2023 at 8:58:49 PM UTC-5, anti...@math.uni.wroc.pl wrote:> Rick C <gnuarm.del...@gmail.com> wrote: > > On Friday, January 20, 2023 at 4:02:27 PM UTC-5, Dimiter wrote: > > > On 1/20/2023 22:37, Rick C wrote: > > > > On Friday, January 20, 2023 at 1:17:59 PM UTC-5, Herbert Kleebauer wrote: > > > >> On 19.01.2023 19:06, Rick C wrote: > > > >> > > > >> > > > >>> You aren't making sense. There are literally hundreds if not > > > >>> thousands of boxes with two serial ports. Some have only that. > > > >>> Others have extra ports. But none are programmable. There > > > >>> are lots of programmable controllers with dual serial ports, > > > >>> but not in an enclosure. > > > >> Seems you are 25 years to late. But this company is still selling > > > >> its device (with a Z180 processor). Seems this is what you are > > > >> asking for (but maybe without the price): > > > >> > > > >> https://www.kksystems.com/programmable-protocol-converters/ppc-4-h2-c.html/ > > > >> https://www.kksystems.com/datasheets/pdf_files/ppclft.pdf > > > >> https://www.kksystems.com/datasheets/pdf_files/ppcman.pdf > > > >>> Alibaba is literally the last place I would by something like > > > >>> this, for all the obvious reasons, including the risk of never > > > >>> Yseeing the product or your money again. > > > >> > > > >> I bought many things from Aliexpress an nearly never had > > > >> any problems. > > > > > > > > I'm pleased for you. People safely cross streets outside the crosswalk, yet people are killed doing that every day. Do you tell your kids it's a good thing to do? > > > > > > > Buying a $10 or a $100 thing at aliexpress is not that similar > > > to getting killed, you know. > > > I have bought a lot of small stuff there and have not yet been killed. > > > Oh yes, and I do cross streets as I please and I am still alive, but > > > that's not a very similar matter, as explained above. > > > > My experience with Alibaba is not the same as yours. With Ebay, I can dispute a sale and get a refund. Alibaba spent literally months demanding more and more things from me, many which made no sense because of the language barrier. In the end, they said I failed to prove the vendor was lying when he said he shipped the item listed. Photos were not good enough. They wanted a video for some reason. Alibaba simply does not support their customers, so I don't use them. Ebay is worth while, but some things sold are perpetually fake, or crap and you have to buy them to find out, then make the "return", which the vendor is required to pay for, so they often say keep it. > > > > I even bought crap wire on Ebay from a vendor relatively local. The actual wire gauge was about three numbers below the claimed AWG. Bought 20 gauge and got 23 gauge. Bought 18 gauge and got 21 gauge, etc. I was getting the refund, so I thought I'd try seeing how far this went. 16 gauge was actually 19 gauge and 12 gauge, was actually 15 gauge. The vendor could not say they didn't know, the wire insulation has *their* name on it! So it's a custom marked product. How could they not know they are selling mislabeled wire? > > > > Yeah, they all sell crap. I just find it possible to get a refund from Ebay. Alibaba, not so much. > > > IIUC Alibaba is intended for larger transactions and has different > rules than Aliexpress. I did only small or very small transactions. > For me problem with Ebay was that with cheap shipping things would > not arrive and there were no way to dispute this.I've had exactly that problem. The only issue is that the vendor will ask you to wait another week or two, and repeat that process until the 60 day window has closed. So I say, no, I want a refund. Even if they don't cooperate, Ebay has always provided a refund. This has happened maybe four or five times. Once, the ordered item really did arrive.> I can understand > this, without tracking there is no way to know who was to blame: > seller, mail or fraudolent customer. Tracked shipping was > significantly more expensive than goods that I wanted to buy. > OTOH things with cheap/free shipping ordered on Aliexpress were > arriving fine. So my conclusion was that Ebay sellers were at > fault and I stopped buying on Ebay.The shipping on Ebay has improved. Very few of the vendors now use untracked shipping. But even if the tracking says it was delivered, you can still get a refund for an undelivered item. The shipping company does not always deliver to the right home or mailbox. Sometimes people give it to you, other times they don't. In any event, again, I've never been turned down for a refund by Ebay if I do everything right that I'm supposed to do, which is mostly, report it within 60 days of ordering. Once a Japanese company shipped an item wrong. I don't recall the detail, but they wanted me to pay the return shipping which was not cheap. I dug my heals in and eventually lost. Don't recall the reason why. They stopped receiving my emails, or any other communications. So I opened another account, ordered the deluxe version of the same thing, shipped to another address. I made a claim with the credit card and got the refund. Then I sold this one to pay for the loss on the other one. Maybe that was dishonest, but I feel I was cheated on the first order, so justified. I also ordered a Hantek attached oscilloscope, the low end model, to evaluate before buying a higher end model. I couldn't even get the software to load. No support to speak of, so I put in for a return. For whatever readson, the tracking was mucked and said it was never delivered. So I got the refund without an argument. Hantek is real crap goods, btw.> There was period when also some shipments from Aliexpress vanished, > but AFAICS Aliexpress got this under control: they have reasonably > cheap tracked shipping and it seem that on all shipments they track > if package leaves China. That probably removes all incentives > for sellers to fail sending things.No, they send something, just not anything of value. Aliexpress can't seem to understand the ICs which don't work, are counterfeit and you don't have to test every one on the reel to know they are all crap. The real issue was the language barrier. They don't speak English, rather use automated translators in both directions, so don't understand half of what you are saying. They also don't understand what an IC is and think counterfeit is only for handbags.> Most Aliexpress seller have resonably high volumes. They sell > what customers want to buy. It can not be completely non functional, > there are not enough fools to support this.LOL! If they buy counterfeit ICs at $0.05 each, they don't need to sell many at $5.00 to make profit.> The problem is > that most customers are unable or unwillig to fully examine > what they bought. So you get rechargable batteries with > completely bogus stated capacity or USB chargers with inflated > charging current. I bought a lot of things on Aliexpress > but I am trying to keep realistic expectations. I bought > few USB chargers knowing that stated current (2.1 A) is > much bigger than real one (0.85 A), but they were good enough > for my purpose. I bought resistors and small power transistors. > My reasoning was that making something that looks like resistor > or transistor in small/medium volume is probably more expensive > than real resistor/transistor in high volume. And hopefully > there are not enough fools to fund high volume manufacturing > of fake transistors.I don't think you understand. There are any number of things that look like the thing they are selling you, which will pass a visual inspection if you close one eye and have no idea what you are looking for. But they are fake. Even a $0.10 transistor has a lot of markup if they only pay $0.001 each for a reject. It might work well enough to light the LED on a transistor tester.> Well, I got resistors and resonably > performing transistors. I can not say if there are some hidden > troubles but to the moment I am satisfied with what I bought.Sure, if you only need crap components, then you are good to go!> In the past I bought few STM chips from Chinese sellers. > AFAIK those chips were widely used in China, the unit price was > much lower than unit price from western distributors, but > significantly higher that supposed volume price. So it > looked resonable that Chinese seller could sell them at lower > margin and still make a profit. And up to now I had no > problem with those chips. > > OTOH if there is advanced/rare western part it would be strange > if Chinese seller had some magic cheap source of the part, so > I am very suspicious of such offers. Power mosfets were > borderline case. Around 2019 I bought packs of 10 from several > sellers. Essentially all were out of specs (too large Rds_on). If > there were moderate discrepancy I made comments stating real paramenter, > in few cases of really large discrepancy I requested partial > refund (and got it possibly after a dispute). To say the truth, > refunds that I got were probably not worth my time, I did this > mostly from feeling of moral duty, to make sure sellers know > that there is problem and to discourage them from selling such > bad parts. > > When buying on Aliexpress it is useful to read buyers comments. > Especially Russians tend to measure/test bought parts, so you > can have resonable idea what you are buying.I've never found any selling sites with good reviews. Many are made up from whole cloth. I recall when Ebay had some sort of rating system in both directions. There were vendors who would set up buyer accounts and buy things at a penny. Good reviews in both directions and credibility would increase. Eventually Ebay put an end to it, partly by all but eliminating reviews of buyers. Now, I find very few sellers with fewer than thousands of ratings. If they have few ratings, or are below 99% positive, I avoid them if I have choice. One thing I've learned is to completely avoid flash drives on any of these sites. 90% of the time, they will fail a good memory test. Seems they use a flash drive 8 or 16 times smaller and flip the bits on the size reporting. They can sell a bunch of these before they are booted off the service.> BTW: classic Arduino boards are supposed to have Atmega 328P. > I have heard that recently a lot of boards instead had Chinese > chip. IIUC such boards also appeared in western distribution > channels, so it is possible that some Arduino boards that you > use is equpped with Chinese chip. On paper Chinese chip should > be better than Atmega 328P, but it has incompatiblities. For > simple use in Arduino it may be compatible enough, but in case > of troubles difference between chips is one of possible reasons.I don't have details, but I'm pretty sure they are using an actual Arduino nano from the original Arduino vendor. You'd think they are buying from mainstream vendors, no fakes. -- Rick C. -++- Get 1,000 miles of free Supercharging -++- Tesla referral code - https://ts.la/richard11209
Reply by ●January 20, 20232023-01-20
Theo <theom+news@chiark.greenend.org.uk> writes:> What is the use case for a programmable RS232-to-RS232 product? If > you can think of a use case, maybe you can find somebody who makes > such a thing.The search is not for an RS232-to-RS232 product per se, but for a small computer with two RS232 ports. In the Z80 era, those used to be plentiful. Of course they were considered full fledged personal computers, in large expensive boxes, given the technology of time. The lament is that there doesn't seem to be anything like that being made today with modern technology. Just a small box with a programmable microprocessor inside, and two RS232 ports. All the available products add a massive amount of additional complexity. It does seem like an opportunity. Imagining making something like that for myself makes me feel dismayed. Besides the MCU board and enclosure, you also need a bunch of mounting screws, standoffs, connectors, an enclosure made of sheet metal, tools to drill holes for the standoffs and make D-shaped cutouts for the DB9 connectors, burn-in testing for everything, yada yada yada. All that stuff would have to be ordered from someplace, maybe multiple places. Whenever I try to make anything physical, I invariably discover partway through that I need some 10 cent part that I didn't think of earlier, so I have to order that and wait N days for its arrival, then repeat this process several times. This is why custom made anything costs so much. It's not like programming where if I need some chunk of software, I can download it and have it a minute later. It doesn't seem like THAT outlandish a wish to hope that box described instead exists as an off the shelf product from somewhere. It is weird that it is so hard to find.