We produce time & attendance software. My area of concern is using modems to communicate with embedded-system time clocks. We have been communicating with 2400 & 19200 bps time clocks for years with our software using multiport DigiRAS products. When we switched to a USB Digi Rapidport, communications to the 19200 bps devices are working fine, but when dialing out to 2400 bps device, it comes back with "NO CARRIER" after about 4 seconds. Both are using the same phone lines (manually switched between DigiRAS & Rapidport as needed). The initialization string in use is "AT&F0E0W2" on RapidPort. The result code using "AT#UD" is 50, "AnyKeyAbort". This is a software application, so there is no character output after the dial command for at least 60 seconds. I think our software can be ruled out, as the same software works fine with DigiRAS, with a different initialization string, of course.
What can I try? This error makes no sense.