GSM (iDEN) cellullar modems - Networking Connectivity Issues
 

I am looking for some good (working?) references or direct help.
When doing GSM modems, you have to give it the correct AT commands.
I have PDF reference files on the AT commands, but which ones, in which order and with what parameters is the the question. I have been working on this for over 4 weeks and have frustrating times and little successes, but have not had a big break through.


WHAT: I want to connect the linux SBC to the Internet by way of a GSM (iDEN) modem using PPP.

CURRENT: I have found this order for connecting.
ATZ2
AT+WS46=24
AT+WS45=4
AT+WVCLASS=9
AT&W2
ATDS=2

The dialing of the S=2 seems to dial something that I am assuming is the saved (&W2) two parameters. I added this to the chat script for startup of the PPP.

Okay, so I get the "connect" finally. the SBC finally goes on line with a PPP0 driver and an IP address. It is a local 10. number and the gateway is a 10. number. But no pings to the outside world.

BEFORE CONNECTING:
I do a "at+wpstate" and get info that the modem is PACKET service type, 65.76.xxx.xxx VALID NEI (which is the fixed IP address from NO service Next tell ). the modem is registered and the MIP is registered also.
I do a "at+wv305?" and the MIP home agent address IP is "170.206.xxx.xxx"
I do a "at+wv324?" and the dns ip's are "170.206.xx.xx" "170.206.xx.xx"

AFTER CONNECTING:
I can ping the local 10. PPP0 ip. I can not ping the 10. gateway or 65. or the 170. ip numbers above.
I have a route of all addresses going through the 10. gateway mentioned.
I do not see where the modem 10. gateway and the 65. NEI IP address are connected. Does the modem do that internally? Do you have to enable it some how? I have checked with the modem vendor, not much help yet.

Bottom line: What am I missing? What more do you need to know to help me solve this problem?

Some answers to the questions (route)
 

routing appears to be part of the problem.
check the systems route tables. "route"
if their is a default route, then the PPPD will not create one.
You may need to use the route command to add or del routes.
Be very aware of what routes are being made or deleted.
this area is a little of Black Magic, until you understand it.

so i deleted the default route and then restarted the PPPD and a new default route using the 10. ip numbers. So now I can get out bound.

Inbound is still a problem. it uses a 65. ip number from the outside world.

The connection goes wacko after 30 to 90 seconds
 

The route appears problem appears to be fixed.
delete the existing route, and pppd will add one for you?
I think that is what it did.
now the system pings the outside world, but the ping stops after 30 to 90 seconds.
A full reset is needed to get it running again.

The outside world could not get inside to the box.
so I added some mystic at commands.
at+wvvip=1,"10.23.6.2"
yep, got have the " or it does not work.
at+wv330=1,80,80,6,"10.23.6.2"
yep, the " again, got to have them.
these appeared to allow the outside world into the box where open ports were.

It would be nice if the manufactor, knew how to write manuals that explained the AT command set usage and interaction to make different things happen. Maybe working sample code. But alas, that is asking to much of a battery eliminator company.