Thanks for the info oded. I realize a gsm modem isn't that great but it should be ample for a small chat service through a website. A hosted gsm modem based solution will be costing £1000-£2000 a year so if I duplicate that myself why not. Deltica list 1msg/2secs for their service whereas most others do give your figure of 1msg/5secs (don't know how they get this better performance.) http://www.skymo.com/sms/docs/interactive.html
I came across this site on the net that listed 1msg/2sec because of smsc queuing. "Ah but what about messages per second I hear you cry. Well a little known fact about the GSM protocol is that it allows queued messages to be concatenated in the conversation between SMSC and Cell Phone. In layman's terms for your Nokia 6210 to receive a Text message takes about 5 seconds. Most of that time being taken up with the "are you there", "I'm sending you a message", "have you got the message yet" type bits. If the SMSC has several messages qued for delivery then the protocol overhead of this type is greatly reduced allowing you to receive a message every 2 seconds." http://www.hogbin.com/ If I remove the keepalive cmd command at least that will be one less at command the modem has to handle. + my modem says it supports xon/xoff software flow control so I might change the com port settings in my bios. What gsm modem do you use out of interest? G.
