GPRS or Edge Howto?

Great! The response is coming back prefixed with +RECEIVE, not +IPD. Seems odd (I'd expected IPD after the call to CIPHEAD), but it can be changed easily...

// Instead of ipdHandler:

//Handle +RECEIVE input data from SIM900A
function receiveHandler(line) {
  var colon = line.indexOf(":");
  if (colon<0) return line; // not enough data here at the moment
  var parms = line.substring(9,colon).split(",");
  parms[1] = 0|parms[1];
  var len = line.length-(colon+1);
  if (len>=parms[1]) {
   // we have everything
   sockData[parms[0]] += line.substr(colon+1,parms[1]);
   return line.substr(colon+parms[1]+1); // return anything else
  } else { 
   // still some to get
   sockData[parms[0]] += line.substr(colon+1,len);
   return "+RECEIVE,"+parms[0]+","+(parms[1]-len)+":";­ // return RECEIVE so we get called next time    
  }
}

// ...


var connect = function(usart, connectedCallback) {
  gprsFuncs.at = at = require("AT").connect(usart);
  require("NetworkJS").create(netCallbacks­);
  at.register("+RECEIVE", receiveHandler); // <----------------------------
  gprsFuncs.reset(connectedCallback);
  return gprsFuncs;
};

Sorry for not getting this sorted for you last time - I've been a bit busy. I did buy the second GPRS module, from a UK seller, but I still wasn't getting a mobile connection so couldn't get anything working :(