From [requestSetupDataCall()](https://github.com/mozilla-b2g/platform_hardware_ril/blob/master/reference-ril/reference-ril.c#L1862) in [hardware/ril](https://github.com/mozilla-b2g/platform_hardware_ril):
```
asprintf(&cmd, "AT+CGDCONT=1,\"%s\",\"%s\",,0,0", pdp_type, apn);
```
and [handleDefinePDPContext()](https://github.com/mozilla-b2g/platform_external_qemu/blob/master/telephony/android_modem.c#L2272) in external/qemu:
```
return "+CGDCONT: (1-1),\"IP\",,,(0-2),(0-4)\r\n";
```
I think Android modem implementation has initial PDP context concept built into the code, so we'll need a position for that initial context. `id = cmd[0] - '0'`, I mean.