RFID Scanner devices over VPN?

[Guest]

Has anyone had any experience using RF barcode scanners over a VPN tunnel? Does that matter at all for connectivity?

The reason I ask is as follows:

I have a set of Intermec CK71 scanners that I am trying to get working at my small business to keep track of inventory in the warehouse. The scanners are set up to use the existing WiFi network, and I can they operate by establishing a telnet prompt with a remote system. Our database server is actually located in a remote hosting facility, so all our PCs connect to it via an established VPN tunnel.

The problem seems to be when we try to use the scanners, we get a login prompt on them, we log in fine and get the inventory menus we expect. But after a few minutes, we get disconnected like the telnet session was dropped orthe WiFi signal was lost. We are confident that the WiFi is not the problem because signal strength never waivers and has been tested for gaps and such by a networking professional.

I'm wondering if because the telnet session is coming across a VPN tunnel that it may be being dropped or be seeing some sort of idle timeout even though the session is actually active? We've tried looking at many different areas and tried many things but can't seem to figure out why this is failing.. Same RF equipment seems to work fine at the central location where our database server is hosted.

 

[Paul]

Has anyone had any experience using RF barcode scanners over a VPN tunnel? Does that matter at all for connectivity?

The reason I ask is as follows:

I have a set of Intermec CK71 scanners that I am trying to get working at my small business to keep track of inventory in the warehouse. The scanners are set up to use the existing WiFi network, and I can they operate by establishing a telnet prompt with a remote system. Our database server is actually located in a remote hosting facility, so all our PCs connect to it via an established VPN tunnel.

The problem seems to be when we try to use the scanners, we get a login prompt on them, we log in fine and get the inventory menus we expect. But after a few minutes, we get disconnected like the telnet session was dropped or the WiFi signal was lost. We are confident that the WiFi is not the problem because signal strength never waivers and has been tested for gaps and such by a networking professional.

I'm wondering if because the telnet session is coming across a VPN tunnel that it may be being dropped or be seeing some sort of idle timeout even though the session is actually active? We've tried looking at many different areas and tried many things but can't seem to figure out why this is failing. Same RF equipment seems to work fine at the central location where our database server is hosted.

http://www.intermec.com/products/cmptrck71a/index.aspx

"Operating System
Microsoft Windows Embedded Handheld built on Windows 6.5.3 technology"

*******

I'm stumped as to where to go first. On the one hand,
Wikipedia lists a bunch of RFCs for telnet, so perhaps
you could look for a protocol timeout there.

tlntsvr.exe also exists in WinXP, and you could make a
test server out of a regular desktop. Now, I don't know
how you'd go about "faking" the info the CK71 produces,
in order to study the protocol. Perhaps from your
server end, you could do an interactive session, and
then study what happens when you stop typing in the
server-box telnet client, and whether the tlntsvr.exe
on a WinXP desktop box (the telnet server), times out the
connection or not.

FTP used to have a connection timeout feature, so it
would not surprise me to find a Telnet server with the
same kind of feature. I tried to find out if that was
tunable, but didn't find any info I could use.

Paul

 

[Guest]

http://www.intermec.com/products/cmptrck71a/index.aspx

"Operating System

Microsoft Windows Embedded Handheld built on Windows 6.5.3 technology"

I'm stumped as to where to go first. On the one hand,

Wikipedia lists a bunch of RFCs for telnet, so perhaps

you could look for a protocol timeout there.



tlntsvr.exe also exists in WinXP, and you could make a

test server out of a regular desktop. Now, I don't know

how you'd go about "faking" the info the CK71 produces,

in order to study the protocol. Perhaps from your

server end, you could do an interactive session, and

then study what happens when you stop typing in the

server-box telnet client, and whether the tlntsvr.exe

on a WinXP desktop box (the telnet server), times out the

connection or not.



FTP used to have a connection timeout feature, so it

would not surprise me to find a Telnet server with the

same kind of feature. I tried to find out if that was

tunable, but didn't find any info I could use.



Paul

Hi Paul,

Thanks for brainstorming with me. The CK71 is actually running Windows CE Mobile, a bit dated but works fine. I actually have one website that I connect to that uses Java and XML for its inventory scanning options, and that package is fine because it does not need a dedicated session like the older software I am using which operates on a telnet session.

I may try switching to SSH and see if that makes any difference. I think I can activate the SSH between these scanner clients and the UNIX server we are trying to connect to.

And if I can find a TCPIP sniffer, I may try the test you indicated. Hook up via a laptop and see what happens to the connection. I want to compare the wired vs wireless signal and see if there is anything different I spot.