Connecting to Remote Locations

[TimWilborne]

I am looking for a way to connect either through the internet or phone to some remote locations, the only catch is that LAN lines are not an option. I have been looking a satellite internet and some cellular services but thought some of the members here may have already been down this road. The bandwidth and connection time requirements are low. Probably log 100 bytes every hour at the max. The only other time there would be a connection is for troubleshooting. Any thoughts? Thanks TW

[beegee]

cellular can be an option if the data is limited. Two drawbacks: you need coveage of the network over there and you can have big delays in the communication. Standard modem on PC side should be no problem I presume. The only thing you have to check is your protocol passing on the line. Some asics have problems with some protocols like 1,7,e,2 9600 (used a lot in Japan) because you have an 11bit frame.

[TimWilborne]

I don't think speed will be a problem. Can you think of any solutions besides cellular? Thanks TW

[beegee]

standard modem? If price is not an issue you will probably find solutions with satelite, but for that limited amount of data I don't see a real reason.

[TimWilborne]

The problem is the LAN lines are not an option on some of these systems. When they are available they are available we will use VPNs and phone lines but I'm trying to find the best solution for these systems that can't have any type of LAN line

[beegee]

How far are you away from PSTN/Ethernet/Cable/DSL networks? Can you reach one of these networks with a radio modem (limited range depending on the local legislation)

[Ken Moore]

Radio modems are a good choice if there is an outside line within line of sight, range can be upto several miles. The U.S. allows a stronger signal then the EU. 1. Connect a radio modem to field. 2. Connect 2nd radio modem to land line. 3. Dial in or VPN to 2nd modem. Another option would be a GSM modem, would depend on local coverage. I believe you can get plans where you only pay for the minutes on line. Check to see if your area of concern is covered: http://www.gsmworld.com/roaming/gsminfo/index.shtml

[TimWilborne]

What is a GSM modem? Edit - Ken, that looks like what I'm looking for. Anyone got any experience going online through them? Any connection problems. If the speed is slow it won't be an issue.

[Ken Moore]

A GSM modem is basically a wireless digital modem that utilizes the cell phone service providers for access. So, if a cell phone works, you can probably use a GSM modem. Not all cell service providers have GSM service, I know Verizon doesn't, but the other major carrier do. I prefer Westermo units: http://www.westermosales.com/gd01.htm I would contact them directly. Modems are around $500 each and the service is going to be 30-40 per month.

[TimWilborne]

This might be a stupid question but does it require special hardware or do you pretty much plug a cell phone into it and it require a special GSM service?

[Ken Moore]

Enterton now sells GSM modems with service: http://www.entertron.com/gsmgprsmodem.htm I believe most GSM modems transfer data at fax machine speeds, something along the line of 14.4k baud. NO cell phone required, just connect the plc or other serial device to the modem, uses standard AT commands.

[TimWilborne]

Ok thanks Ken, looks like I need to put in a call to Stephen Luft

[beegee]

Wavecom and Siemens also have cellular(GSM) modems. We have had quite good results with Wavecom (price under 200€ , that's 250$) by the way, Wavecom does support 11bit, we used it on OMRON plcs

[TimWilborne]

Thanks. I found the Wavecom but can't seem to find the Siemens. Do you have a link? Thanks again TW

[beegee]

Check for Siemens M1, M20 and TC35 in Google for local suppliers (I can give you links but mainly in Europe ) By the way, I thought the wavecom is also with a Siemens M1 chipset

[Sleepy Wombat]

TW when you get the GSM you need to get a SIM card of cause,,, most likely get the SIM card to have DATA calls enabled.

[TimWilborne]

Not quite following you Sleepy, can you explain? Thanks TW

[Sleepy Wombat]

Basically what you a getting with a GSM modem is a industrialised mobile phone that talks on the GSM network.... Here in Oz, to get the "mobile phone" to work you need a SIM card (Subscriber Identity Module), as i am sure that this is the case in the states... Now by default your SIM card will be set up for voice/SMS calls... There is another mode called DATA mode available as well (I think that it had more to do with the carrier service provider). I had to specifiy that i wanted this... might be different over there.. but been a while since i had to do this so things might have changed.

[beegee]

In Belgium this is available with each SIM card but not all operators activate the data service by default. You could also consider GPRS or UMTS but I have no experience with those possibilities.

[swimmy67]

TW, Here is another Cellular Modem that I have been looking at. http://www.multitech.com/PRODUCTS/Families/MultiModemEDGE/ I hope this helps.

[TimWilborne]

Yes, thanks Swimmy

[504bloke]

I am currently working on a project that will be using a MultiTech GSM Modem (MTCBA-E) It will be on a remote pumping station for alarm dial out. There is no PLC in the cabinet only some SSD Drives and a Redlion G303, the G303 will be connected to the modem.

[TimWilborne]

I'm leaning towards the MultiTech also. Looks like Sprint has a 40mb plan for $39.99 and an Unlimited mb plan for $59.99. 40mb seems like a plenty when your just polling data, no graphics. Think that will be enough?