FORTUNATELY THE DESIGNERS OF WIRELESS MODEMS ARE AWARE OF THESE PROBLEMS AND THE DEVICES GENERALLY INCLUDE ONE OR MORE MECHANISMS TO ALLOW THE USER TO OPTIMISE THE TIMINGS TO SUIT THEIR APPLICATION

摘要

An obvious hardware solution is to provide an additional logic input to the device, which inhibits the modem's start-up and packetising functions, while still allowing data to be loaded into the transmit buffer. The user asserts this input once all the data in a burst has been loaded, permitting the modem to complete its transmission operation. The name given to such a signal is not standardised. Some suppliers will use a simple description, while others will attempt to relate it to one of the defined RS232 handshaking lines (RTS or DTR for instance). This approach gives optimal control over the burst transmission timing (allowing more complex synchronising and timing schemes to be used) and avoids complex re-programming of the modem device, but calls for extra user hardware.