User's Manual

MaxStream 9XStream™ Wireless OEM Module Manual v2.8

Confidential and Proprietary, ©MaxStream, Inc. 2001

Serial Port Operation

The 9XStream modules come equipped with a CMOS-level asynchronous

serial port, which provides direct communication with any device having a

UART interface (Universal Asynchronous Receiver-Transmitter). The serial

port can also communicate with a COM port on a personal computer, or other

RS-232 port via the MaxStream interface board. By connecting the 9XStream

to the serial port on a host device, the host becomes a wireless communication

device. To transmit, the host device simply sends data from its serial port to

the 9XStream and the 9XStream converts the data into spread spectrum, FCC-

approved wireless data. The data is then detected by a receiving 9XStream

module, checked for integrity, and sent to a receiving device via the serial port

(Figure 2a).

Serial Pins

Figure 2a above shows 4 data lines needed to interface from a microcontroller

or RS-232 device to the 9XStream modules. These four lines represent DI

(Data In), DO (Data Out), CTS, and RTS/CMD (request to send/command

mode). (All low-asserted pins are distinguished with a line over the top of the

pin name, or a ‘*’ symbol prefacing the pin name.) While the DI and DO pins

are indispensable in almost all cases, the CTS and RTS/CMD may not be

needed under certain conditions. The following includes a brief description of

each of these pins and under what conditions the pins must be used. A brief

explanation of the CONFIG pin is also provided.