We mistakenly changed the serial port interface to 230400 bps. Now we find that we don’t have a computer that supports that speed to change it back to 115200. Is there a method to change the unit back to factory default so we can talk to the unit?

It sounds like the TA has had a fixed speed mode (%S2 or %S3) of 230400 baud stored. The method for changing from top speed mode (%S1) or fixed speed mode (%S2 or %S3) back to autobaud mode (%S0) is to send a break or type a character ('@' works best) at a slow baud rate (such as 9600 baud) within the first 10 seconds after power-up of the TA. This fixed-speed escape method is for situations where the TA was configured for the top baud rate of the TA and stored by using&W0. If the TA is used by a computer or terminal that cannot operate at the top baud rate of the TA, then this escape method must be used to recover autobaud mode (%S0) and be sure to store %S0 using&W0 if the TA will no longer be using the top speed or fixed speed modes. In summary, do the following with the TA using a terminal program such as HyperTerminal for Windows: power off the TA, power on the TA, within 10 seconds after power-up (within 10 seconds after the LEDs have stopped cycling) type the '@' symbol (the "at" symbol is Shift-2 on the keyboard), and then give the command AT%S0&W. If you continue to have trouble you may call for technical support.