HL 7748 TCP Connection


I have a mangOH red board with an HL 7748 in it. I have received a CAT M1 sim card for it from Aeris/ Neo (is there a Sierra Wireless CAT M1 trial SIM card out there?) With this HL, I have to do everything via AT commands. I setup the APN using +cgdcont and then attach it to the network with +cgatt. Everything looks good, +creg says it is registered to the home network, +cops gives me 0,0,“AT&T”,7 (which looks good), and I can get an IP address using +cgpaddr. SMS messages for the most part are working,but I am now trying to setup a data connection to talk to a web server. So first, I am just trying to setup a TCP connection using the example in the documentation I have. They include this code…


AT+KTCPCFG=1,0,“www.google.com”,80 Set IP address and port number
Returns session ID 1


AT+KTCPCNX=1 Initiate the connection


The first command (AT&K3) responds with OK, but any other command I try responds with ERROR. Are these the correct commands for LTE? With the +KCNXCFG, it has ‘GPRS’ as a parameter and this is an LTE module. Also, since I have configured the APN already with +cgdcont, do I need this command? I have also tried many other commands from the TCP section, but everything just returns with ERROR. Even when I try AT+KCNXCFG=?" I get an error. So was wondering if anyone has used an LTE HL chip for TCP connections and could let me know what the sequence of AT commands should be for this. I can’t really find much documentation about this anywhere…