Well, I saw someone talked about Beiming GPIB interface in this thread, and I happened to be the one who build up this small toy, so I do feel very happy to be mentioned here several times.
I saw someone said Beiming is the OEM vendor for Keysight/Agilent
. Well I'm sorry that's not correct, Beiming is just a tiny company with just one employee (it's me), and Beiming doesn't have any connection with Keysight/Agilent.
I start this project 5 or 6 years ago, and by that time, I was very curious why Agilent 82357B was that expensive. I think maybe I can make some thing really cheap and good enough to use.
Originally, I hope to use FPGA to build IEEE488 protocol inside by myself, but shortly found that is too much work. So I changed to the way same as Agilent does, using NI chipset instead which could greatly ease the work.
So if you open S82357, you will be able to see NAT9914 and 75ALS162, 75ALS160, which are same with Agilent 82357B. I'm also using the same USB controller as Agilent does, which is CY68013.
You guys may not know, NAT9914 is not cheep. From NI sales channel, this chip is about 20 bucks, and with 75ALS162 and 75ALS160, they may cost over 40USD, which is too much for me. But good thing is, here is China. And you can always got low cost stuffs. I search on Alibaba and found someone sell NAT9914 at 6 buck, I thought they must be faked chips, but what surprised me is, it works as well. From this vendor, I got all the GPIB related chips with much lower price, which made this project more feasible. I still have no idea how they got those cheap NI chipset from, maybe refurbished ones?
The USB controller part software is developed by myself. Because I hope it could be compatible with 82357B or Agilent IO environment, I need to analysis the communication between 82357B and PC, there are plenty of software help to capture the data package over USB for analysis. I tried with many different combination of instruments and software, and try best to cover all circumstances. I remember paid 300 bucks to rent a R&S CMU200 for one week just to make sure S82357 works with it. And that's why I'm keep updating the firmware in past few years, which bothered a lot of customers. I do feel really sorry for that. I also got a lot of help from different people, I remember some one helped capture USB log and email to me for trobleshooting because I can't got his instrument which is working in IEEE488 legacy mode. There is another gentleman helped me to try my Linux driver with his setup (he is in this thread too), I have generate 4 or 5 different version for him and he keep providing me the feedback. I made some really good friends during this process and had a lot of fun here.
What most ironic to me is, although I'm working on a counterfeit 82357, there are also someone trying to counterfeit mine. Someone from Shenzhen bought a very early version S82357 and just use the same design and firmware to sell at a lower price, which is quite a surprise. So after that, I add a small trick to my EEPROM, and made them not able to copy my firmware that easy. That's why there are some not fixed bug keep existing in their version.
Later I made a new version GPIB interface called F82357, which support DMA mode and make the communication speed faster for block transfer. Agilent 82357B support this function, but it took me some time to understand how DMA works over GPIB. F82357 share the same hardware with S82357, the difference just lies to firmware.
Another thing you may ask is, has Agilent contacted me for doing this? The answer is yes, I got warning message on ebay told me not to mention Agilent with my prodcut. I also found one gentleman bought a S82357 and a F82357 on ebay and shipped to an Agilent office in Colorado. I think they have analyzed my work, and found the software was developed by myself, so they decided to let me away. I should attach a greeting card with my GPIB interface together.
And in 2014, I found people sell real Agilent 82357B on ebay with very low price, and I start to know my GPIB interface business is done. I think those Agilent 82357B is true, I bought one and compare with mine which I got from Agilent dealer, the hardware are identical, and it works fine. I thought they came form some big contract manufacturer sites like Foxconn. They used to bought thousands of 82357B for their manufacturing project, and when the project is done, all those equipment comes to the second hand market. I stopped my business on ebay, which took too much of my time on packaging, debugging and supporting works with very small margin.
So feel free to buy the Agilent 82357B on ebay , and enjoy the low price, I think they are true with better quality and reliability.