3.0 Modem Setup Options
NOTE
The Modem also supports a CTS option intended only for V.33 and Bell 208A/B operation, described later in this chapter.
The CD to EIA option is available for Hayes, V.25 bis, and Dumb modes.
•NORMAL — Carrier Detect (CD) is on while the modem is
•TRUE — CD follows DTR supplied from the DTE.
•TOGGLE — CD turns on whenever DTR is present and then toggles off for 500 ms upon disconnect, allowing the attached DTE to recognize that the call is ended and the connection is dropped.
The DSR to EIA option is available for Hayes, V.25 bis, and Dumb modes.
•NORMAL — Data Set Ready (DSR) is on while the modem is
•TRUE — DSR follows DTR supplied from the DTE.
•CROSSOVER (XOVER) — DSR is ON without DTR and toggles for 500 ms upon local or remote disconnect.
The DTR from EIA is available for all modes. It allows you to force the Data Terminal Ready (DTR) signal on (TRUE), which may be needed if your computer or communication software does not supply a DTR signal.
•NORMAL — DTR is supplied by the DTE.
•TRUE — The DTR signal is internally forced ON regardless of the DTR status at the interface.
The DTE Control Of ALB (ALB- DTE Ctrl’ed) option is available for all modes. Analog loopback (ALB) testing can be initiated from the DTE via pin 18. Positive voltage activates the test, whereas negative voltage results in normal operation. Disabling this option keeps the modem from responding to pin 18.
The DTE Control Of RDL (RDL- DTE Ctrl’ed) option is available for all modes. Remote digital loopback (RDL) can be initiated from the DTE via pin 21. Positive voltage activates the test, whereas negative voltage results in normal operation. Disabling this option keeps the modem from responding to pin 21.
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