If you own a no-name or cheap Chinese GPS tracking unit you must read following information.
Different manufacturers and sellers brand their devices under similar popular names (e.g. TK102, TK103, GT02A, H02 and other), so it's impossible to identify correct port and protocol for those devices just by knowing a model name. If you have one of those devices please try all of the following ports:
Please also check for following common issues:
060sis the interval between messages,
***tells the device to continue sending locations periodically and
123456is the default password).
123456789012345, the unique id would be
056789012345. The easiest solution is to register two devices, one with full IMEI and the other one with 12-digit identifier.