Performing a data call

[fpolo]

Hi everyone. In the context of a larger application, I need to transfer occasional, short messages from a cellphone to a PC.

A key requirement is near-instantaneous arrival of those messages; a delay of more than a minute or so would be considered a failure. Since SMSs can occasionally lag due to the network, I am not going to use them.

Rather, I want to build an application on the cellphone that takes the message from the user, initiates a data call to a modem on the PC, and sends the message through. A custom app on the PC will deal with what happens afterwards. Some checksum and retransmit mechanism will make sure of data integrity.

So, I need to know how to programmatically initiate a data call, send data through it, and terminate it. I heard that it's easier to do it with native calls rather than MIDP, but since I'm not quite sure of which phone it will run on and I'm not practical at all with Symbian development, I'd rather use Java.

Can anyone give me some pointers on this? I'm relatively new to MIDP development, and I have no clue on where to start with regards to data calls.

[peterblazejewicz]

hi,

kind of JMS?
http://joram.objectweb.org/
http://www.microjava.com/articles/techtalk/jms
(requires middle-tier)
regards,
peter

[fpolo]

Not exactly. Those links seem to be about asynchronous messaging; storing messages to be forwarded as soon as the network becomes available.

That's very interesting, but what I need is - I hope - much simpler. Probably a textbook newbie question.

I simply want to get the cellphone to dial a number as a data call and send a few bytes through. I can safely assume that the network itself will be up and the receiver will be ready to immediately pick up the call.

[peterblazejewicz]

hi,

you can initiate voice call only via MIDlet.platformRequest(...) method,
no other way i'm afraid yet,
for all other data exchange you can use only GFC:
http://developers.sun.com/techtopics...ericframework/

regards,
peter

[fpolo]

Thanks. Unless I'm mistaken, GFC doesn't have data call either (it does do UDP; I guess I might have the phone talk to the computer via Internet if all else fails).

But platformRequest refers to RFC 2806, which does have a syntax for data calls. Maybe some devices support it? However, I don't see how I would use the connection even if it could be done, since platformRequest only returns a boolean. Seems that platformRequest is designed to start an application and then forget about it.

Given that, is a MIDP data call completely impossible?