The SC932 has jumpers inside to configure how the DTR and RTS lines operate in reference to the data logger’s modem enable line. There are no jumpers to configure in the SC932A; the DTR line is driven always, and the RTS line follows the data logger’s modem enable line. If the SC932A does not work with a modem, the issue may be corrected by disabling the hardware flow control and/or configuring the modem to ignore the status of the DTR line.