prindle@nadc.nadc.navy.mil (Frank Prindle) (09/28/90)
Analog loopback is a test mode in which the modem goes into originate mode on its send half, and answer mode on its receive half, thereby talking into its own ear, so to speak. A properly functioning modem thus tests all of its circuits, both analog and digital, by echoing each transmitted character back to its received data. Not a wholly useful mode for normal operations, it is reserved for testing a potentially defective modem. Since AL mode will cause the modem to drop carrier out the phone line, you generally cannot select this mode if the modem is off-hook. Sincerely, Frank Prindle Prindle@NADC.navy.mil