SB700EX - Force Port connection and flush buffer

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aminotg
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SB700EX - Force Port connection and flush buffer

Post by aminotg » Wed Dec 15, 2021 7:18 am

Hello,

Is there some kind of ethernet command that I can sent the SB700EX to force the connection to a specific serial port and flush the buffer on the SB700EX?

There are many cases when I send "serial data" to a virtual comm port and the data sits in some buffer for a while before it sends it to the serial port or sits in some buffer before the response comes back to my PC. I am communicating with barcode printers and I need these serial transaction to occur in a timely fashion because some commands are time critical.

Thanks for your help

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TomNB
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Re: SB700EX - Force Port connection and flush buffer

Post by TomNB » Thu Dec 16, 2021 8:38 am

You can take a look at the packetization settings and flush the buffer there. But the delays could be elsewhere in your system as well, such as the network stack on your computer. A test to narrow things down would be to try a telnet connection instead of your vcom port and other software, then see if the behavior is any different.

aminotg
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Joined: Wed Dec 15, 2021 7:12 am

Re: SB700EX - Force Port connection and flush buffer

Post by aminotg » Thu Dec 16, 2021 3:33 pm

I tried other software and saw the same behavior, in fact that is how I found the issue. Basically I setup teraterm on two PCs, then created a null mode connection between port 1 -> port 2.

teraterm from PC@1 was connected to the virtual com port on Port 1 of the SB700EX
teraterm from PC#2 was connected to the virtual com port on Port 2 or the SB700EX

I would send data (text file) from PC#1 and would receive it on the PC#2.
When I did this I would see large delays on the receiving computer. Sometimes it would take minutes to show up, or it wouldn't show up at all until I'd send another text file. This is why I assumed the SB700EX was buffering the TCPIP data. The two PCs and SB700EX were all on the same ethernet switch.

aminotg
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Re: SB700EX - Force Port connection and flush buffer

Post by aminotg » Thu Dec 16, 2021 3:41 pm

Attachment shows the TCP Packet settings.
Attachments
TCP_Settings.PNG
TCP_Settings.PNG (172.73 KiB) Viewed 861 times

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TomNB
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Re: SB700EX - Force Port connection and flush buffer

Post by TomNB » Fri Dec 17, 2021 7:26 am

Hello,

Thank you for the additional information. From my previous post, the biggest area of concern is the virtual comm port driver and software applications that rely on it for this test, such as teraterm. If you do not use a virtual comm port driver at all, and instead use native telnet to talk to the device, do you see a delay? You should be able to copy/paste files if you need to, but also just type and see if there is a delay. Nothing should be buffering/delaying for minutes at a time, and I'm not seeing that behavior here.

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TomNB
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Re: SB700EX - Force Port connection and flush buffer

Post by TomNB » Sat Dec 18, 2021 12:08 pm

Another question: how large is the file you are sending, and what baud rate are you running at? The TCP stacks on both the PC and NetBurner device will buffer thinks on the network side if the serial buffers fill up. The network is running at 100Mbps, so it is significantly faster than a serial port, and the network side will use flow control.

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