The modem configured will display as two serial USB ports. The first port is for initialization, dialing and data transmission, and the second for request / monitoring. The modem is controlled via two ports using AT commands. You can see how everything works by opening ports using HyperTerminal, issuing commands to them and watching the responses. The teams are mostly general, but there are some of their own.
AT^SYSCFG=2,1,3FFFFFFF,1,2 for GPRS/EDGE Preferred AT^SYSCFG=2,2,3FFFFFFF,1,2 for 3G Preferred AT^SYSCFG=13,1,3FFFFFFF,1,2 for GPRS/EDGE Only AT^SYSCFG=14,2,3FFFFFFF,1,2 for 3G Only
The third parameter, 0x3FFFFFFF instructs the card to use all ranges. A value of 0x400380 here means only GSM900/1800/WCDMA2100 , and a value of 0x200000 here means only GSM1900 .
I don’t know what the last parameter “1,2” is for. But for some of them, for some reason, there should be "2.4".
Status updates from the second port are prefixed with a carriage and have the following forms:
^MODE:3,2 indicates GPRS ^MODE:3,3 indicates EDGE ^MODE:5,4 indicates 3G ^MODE:5,5 indicates HSDPA ^DSFLOWRPT:n,n,n,n,n,n,n n1 is the duration of the connection in seconds n2 is transmit (upload) speed in bytes per second (n2 *8 / 1000 will give you kbps) n3 is receive (download) speed in bytes per second (n3 *8 / 1000 will give you kbps) n4 is the total bytes transmitted during this session n5 is the total bytes transmitted during this session n6 no idea, but I always get 0x1F40 (8000) here n7 no idea, but I always get 0x7530 (30000) here
You can reset connection statistics by sending AT^DSFLOWCLR .
Information on how to initialize the device can be found here :
Additional information here and here :
Another thing is that the formatting of responses from e220 varies slightly with the firmware version.