Someone else had a similar problem expecting to use AT commands with such a device.
He found that it uses a proprietary command set. He had to go to a website to find out what series of letters to type, in order for the device to respond.
There are threads that have to do with a similar topic at this message board. Such posts often mention modem related words.
Try a search at this message board for modem related words such as baud, parity, etc.
Also search on the brand of your device and the model number, etc.