DART 200 CDPD Modem User’s Guide | 8 Application Programming |
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NOTE:
In general, do not design equipment with less than these basic eight leads to avoid potential application programming limitations.
Table 8-1. Telemetry options for PAD Mode
Command | Description |
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\O0 | Select PAD Mode | ||
| ∙ | F0 | Local echo in online mode |
| ∙ | \M1 | Enable manual data forwarding |
| ∙ | \T0 | Disable automatic data forwarding |
\O1 | Select Telnet Mode | ||
| ∙ | F1 | Remote echo in online mode |
| ∙ | \M0 | Disable manual data forwarding |
| ∙ | \T1 | Enable automatic data forwarding |
After changing \O be sure to verify that the coupled parameters are still set appropriately.
Data and control interface
The DART 200 uses the following eight leads on the
∙Carrier Detect (DCD) - Optional**
∙Receive Data (RXD) - Required*
∙Transmit Data (TXD) - Required*
∙Data Terminal Ready (DTR) - Optional**
∙Signal ground (GND) - Required*
∙Data Set Ready (DSR) - Optional**
∙Request to Send (RTS) - Optional†
∙Clear to Send (CTS) - Optional†
*The DART 200 cannot communicate with the attached device without these three signals. In addition, the DART 200 requires these three signal lines to accommodate firmware downloads.
**If the MAS device can sense and signal on these lines, use them. If not, they can be ignored. These lines are used for signaling between the DART 200 and the (MAS). DCD and DSR pass information from the DART to the MAS, and DTR is used by the MAS to signal the modem.
†Not required if your MAS does not support flow control (\Q0), or if it uses software flow control (\Q1). Provides hardware flow control between the DART and the MAS. This is the default (\Q2) for the DART.
CDPD status sensing
Permits the MAS to determine the following without escaping to command mode, issuing an ATS57?, and testing for specific bits being on:
1. Does the modem still have a connection to the host system?
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