{"id":6938,"date":"2020-03-31T12:45:40","date_gmt":"2020-03-31T12:45:40","guid":{"rendered":"https:\/\/www.use-snip.com\/kb\/?post_type=ht_kb&p=6938"},"modified":"2022-04-06T17:58:01","modified_gmt":"2022-04-06T17:58:01","slug":"rs232-over-the-internet","status":"publish","type":"ht_kb","link":"https:\/\/www.use-snip.com\/kb\/knowledge-base\/rs232-over-the-internet\/","title":{"rendered":"RS232 over the Internet"},"content":{"rendered":"

Connecting a GNSS serial port over the Internet to a remote SNIP<\/strong><\/span> NTRIP Caster is easily achieved using one of the many serial to internet<\/em> adopter dongles available.\u00a0 In this article we describe the setup process using the popular USR-TCP232-302 product made by Jinan USR IOT Technology<\/em> and available from many electronics retailers for about $25 dollars (US).\u00a0 The firm makes a variety of similar products including some with WiFi connectivity if you do not have a physical internet cable (RJ45) near the Base Station.<\/p>\n

If you happen to have a spare PC, or a low cost NUC node, the free Lite<\/strong><\/em><\/span> model of SNIP<\/strong><\/span> can also be used to connect older serial GNSS Base Stations by their serial ports.\u00a0 That has the advantage of using proper NTRIP protocols and security for the connection.\u00a0 In this example we will use the serial to internet<\/em> adapter device and create a RAW connection<\/a> to the SNIP<\/strong><\/span> Caster.\u00a0 These adapter devices simply read in the serial data stream and then establish a connection with common TCP\/IP to the designated remote device (in this case the Caster).\u00a0 But they are not able to add the NTRIP protocol details, hence the need for a RAW TCP\/IP style connection.<\/p>\n

\n

The setup process consists of three separate steps:<\/p>\n

    \n
  1. Initially connecting to the adapter device<\/li>\n
  2. Programming the adapter device<\/li>\n
  3. Programming the SNIP Caster to accept the connection<\/li>\n<\/ol>\n

    Of course you must also program the GNSS device to send the data you need (observations, the precise antenna location, etc. typically all encoded in RTCM3 messages).\u00a0 These settings should then be saved in the device so that when there is a power lose and recovery, you will not need to reset things.\u00a0 We recommend that you power cycle the entire Base Station setup a few times once everything is working to ensure it will recover as desired.<\/p>\n

    Connecting to the Device<\/h2>\n

    Typically half the battle is to initially find and connect to the adapter device itself.\u00a0 In this authors experience, this is the step that often consumes the most time.<\/p>\n

    This is best initially done at the comfort of a desk rather than out in the field\/barn\/shed where the Base Station is to be installed.\u00a0\u00a0 We presume there is a working PC with a working internet connection and a browser.\u00a0 We will use the browser (and a small web page built into the adapter device) to adjust the settings.\u00a0 A common internet cable will be needed as well as a place to plug in the adapter device into a bridge or hub.<\/p>\n

    \u21d2\u21d2<\/strong><\/big><\/span> Plug the adapter device power module cord to the wall and to the device.\u00a0 Plug in the internet cable to your local network.\u00a0 Confirm that you see the normal two lights (current sensing and packet traffic) under the cable.\u00a0 Now that the device is operational, we need to find it on the network.<\/p>\n

    Fresh out of the box (or after pressing the reset button and power cycling) the device IP is set to 192.168.0.7<\/strong> (with a mask of 255.255.255.0 and a gateway of 192.168.0.1). [A basic knowledge of how IP addresses works is assumed here, but nothing of any depth]\u00a0 It does not<\/strong> do DHCP until you program it to do so.\u00a0\u00a0\u00a0 It does<\/strong> reply to PINGs. [Devices from other makes will use other IP values as their defaults]<\/p>\n

    If you happen to be in network where the sub-net 192.168.0.x is reachable, great, you can reach the adapter device without any annoying temporary network changes.\u00a0 Bring up a command prompt and type “ping 192.168.0.7” and confirm this (if it is reachable, you will see the text Reply from 192.168.0.7 bytes=32<\/em> ….).\u00a0\u00a0 You can move on to the next step, Programming the Device<\/strong><\/em>.<\/p>\n

    Many local networks avoid using 192.168.0.x\u00a0 (here we use 192.168.1.x in one office and 192.168.2.x in another).\u00a0 If you happen to be in an office or home that uses 10.10.x.x. or 192.168.xx.yy where xx is not == 0, then you will need to create a temporary network to gain access to the device at 192.168.0.7\u00a0 – but that is really not as hard as it might seem.<\/p>\n

    You only need one PC and an internet cable which you will connect directly between the PC and the adapter device (a WiFi connection is not suitable for this).\u00a0 We will simply copy down the current network settings, then change them, program the device, confirm it works, and then change everything back.\u00a0 Do not attempt this on a ‘network PC’ that loads its operating system from a central server each day.\u00a0 While doing this, the PC will not have access to the internet or to eMail, or any other resources in your local office network.<\/p>\n

    First we need to document what the current network card setting on the PC are set to be.\u00a0 Go to your Control Panel<\/strong>, select Network and Internet,<\/strong> select Network and Sharing Center<\/strong> and then select Change adapter settings .\u00a0 <\/strong>Double click on the Local Area Connection<\/strong> icon for the connection you will use.<\/p>\n

    You should now be looking at a Local Area Connection Status<\/strong> dialog box similar to the below.<\/p>\n

    \"\"<\/p>\n

    In a moment we will change the TCP\/IPv4 settings (under Properties) so we can reach the adapter device.\u00a0 But first we must document the current settings to restore them.\u00a0 If you (more correctly, your office environment) use DHCP, this is easy, less so if you have entered specific settings.\u00a0 Click on the button marked Properties<\/strong>.<\/p>\n

    \"\"<\/p>\n

    Select (click on) the entry marked Internet Protocol Version 4 (TCP\/IPv4)<\/strong>.<\/p>\n

    Press the button marked Properties <\/strong>and take a look at the displayed screen.\u00a0 It will look similar to one of the two images below.\u00a0\u00a0 The one on the left is a machine using DCHP to obtain the IP values; the one on the right is using manually entered values.<\/p>\n

    \"\"<\/p>\n

    [Aside<\/strong><\/em><\/span>: Each separate connection on your machine has these settings.\u00a0 Here we should be using the physical RJ45 cable connection for the internet, not any WiFi connection or any virtual connections you may also have on this machine.\u00a0 If you do not normally use this connection or cable you may have to enable the adapter to be able to set its values.]<\/p>\n

    If your machine has the radio button checked for “Obtain… address automatically” – please note that for restoring later.<\/p>\n

    If your machine has values entered in the fields, please jot the numbers you see down (or screen capture) for IP address, Subnet mask, Default gateway and any DNS Servers.\u00a0 We will need to restore these values as a final step.<\/strong><\/p>\n

    We can now enter the values shown below so that the PC and the adapter device can see each other:<\/p>\n

    \"\"<\/p>\n

    Save these values.\u00a0 You can check them with the ipconfig<\/strong> command from a command line if needed.<\/p>\n

    \u21d2\u21d2<\/strong><\/big><\/span> Plug the adapter device internet cable directly to your PC, unplugging the cable that was there.\u00a0 The power supply module should be active and plugged in from the prior step.\u00a0 Confirm that you see the normal two lights (current sensing and packet traffic) under the cable.\u00a0 Now that the device is operational, we need to find it on the ‘network’ you have created consisting of just these two devices.<\/p>\n

    You should now be able to PING the adapter device as well.\u00a0 Because your PC and the adapter device are the only devices on this ‘network’ (the cable between you), no other devices can be reached at this time.<\/p>\n

    Open whatever web browser you prefer to use on the PC. Enter the IP for the device (at present 192.168.0.7).\u00a0 If you connect to the adapter device you will see a log on dialog.<\/p>\n

    \"\"<\/p>\n

    Congratulations. The default user and password is admin<\/strong> \/ admin<\/strong>. We can now move to programming the device itself.<\/p>\n

    Programming the Device<\/h2>\n

    The adapter device is programmed with a simple web interface. Similar to many small network appliances, parameter values are set on the web page, then the device is restarted to install the new values.\u00a0\u00a0\u00a0 One annoying detail with the USR_TCP232-302 is that it is built in China and will default to Chinese characters for some of the web page error messages.\u00a0 But all the key pages are available in English (you can toggle between the two with a small icon in the upper right hand corner of most pages).<\/p>\n

    If you have not already done so, log on to the device (user = admin\u00a0 password = admin).\u00a0 You will be presented with a simple web status page.<\/p>\n

    \"\"<\/p>\n

    The tabs\/buttons along the left side are used to access the major controls and bring up a web page for that purpose.\u00a0\u00a0 We next have to set up the permanent IP to be used and then set both ‘sides’ of the device.<\/p>\n