XR60 Dual Serial Port Bug

AirLink Routers
1

XR60
Image: 5.0.86 2024-06-05 00:50:13

When enabling the second serial port, the first serial port stops answering. We use tcp/2101 for port 1 and tcp/2102 for port 2. I can successfully communicate on port 1 until I set the second serial port for PAD and auto answer. Port 1 will not answer on tcp/2101 after activating the second serial port.

2

Hi @mdobak,

Based on your description, I understand that you’re using a serial cable with one end being RJ45 and the other end being a dual DB9 female as described on pages 55 and 81 of the AirLink XR60 Hardware User Guide. You’ve configured PAD mode so that data is transmitted through the serial interface and encapsulated into TCP/UDP messages to be sent to a remote IP associated with the configured port, is that correct? If not, please describe it in more detail.

If that’s correct, could you please share more information on how you configured PAD mode on the XR60? Please share a screenshot of the Hardware Interfaces > Serial Interfaces > Configuration section with me.

You can find the AirLink XR60 Hardware User Guide at the following link: source.sierrawireless.com/resources/airlink/hardware_reference_docs/airlink_xr60_userguide/

Thanks,

3

Hi,

I have an RJ-45 test loopback plug plugged into the serial port. The test plug has the two transmit data pins looped to the receive data pins (Pin 3 to Pin 6 (Serial 1) and Pin 2 to Pin 7 (Serial 2). Just using this to see if the data I send to the modem over cellular gets sent back to me.

Serial Port 1 is set to PAD, PAD Mode TCP, Listening Port 2101, Listen for Connections (Auto Answer) - ON

Serial Port 2 is set to PAD, PAD Mode TCP, Listening Port 2102, Listen for Connections (Auto Answer) – OFF

To verify that SP1 answers (SYN-ACK), I telnet to the modem IP on port 2101. Ex: telnet xxx.xxx.xxx.xxx 2101. I can type on my telnet session and see what I type echo back to me. That shows my path is complete through SP1. I terminate my telnet session for SP1

Now I set SP2 to Listen for Connections (Auto Answer) – ON

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I can now telnet to the modem on xxx.xxx.xxx.xxx 2102 and see my data echo back to me.

When I try to reconnect to SP1, I do not get a SYN-ACK. I cannot connect to the modem on TCP/2101. SP2 still connects.

I would expect that I would be able to connect to either port or both at the same time.

If I reverse the procedure and turn SP2 on first then turn on SP1, SP1 remains active and SP2 will not connect.

Suggestions?

4

Hi @mdobak,

  • Could you please provide a photo of the dual serial cable you are using?
  • With the same cable and the same configuration, did the device ever work well on an older firmware version?
  • Do you have any other XR60 devices? Please try using the same cable, the same configuration and the same AirLink OS firmware as mentioned above to see if issue still occurs.

Thanks,