Sierra Wireless DART 200 CDPD Modem Dart 200 Cdpd Modem User’s Guide Application Programming

DART 200 CDPD Modem User’s Guide 8 Application Programming

With three variables and only two signal lines, decide which two of the three items are most crucial to the application. Usually, RF in range and registration state are tracked. If both of these statuses are present, then a Dial command (ATD) can be issued. To determine more than two items of status the MAS escapes to command mode and reads the network status register (S-Register 57).

∙DTR (Data Terminal Ready) - Transitioning this signal lets the application enter command mode without having to use the escape sequence. To do this, the &D1 (escape) or &D2 (escape and hang-up) option must be selected at initialization time. If this option is used DTR must be held in the down state for a minimum of 15 ms. Refer to Escaping through the control interface, p. 8-16, for more information. The default is &D0 (ignore DTR)

∙S-Register 56 (extended network error codes) - Indicates reasons for a registration failure. Codes 1-7 are suggested in the CDPD specifications but may not be followed by all carriers or infrastructure providers.

1Registration denied - Network Entity Identifier (NEI) may be in use by another device

2Service currently not available

3Invalid NEI (IP Address)

4Insufficient authentication credentials

5Authentication credentials not supported

6NEI has exceeded usage limitations

7Service denied on this subnetwork; try an alternate Provider

250Timed out waiting for home Mobile Data Intermediate Station (MDIS) registration response

251Mobile Data Link Protocol (MDLP) parameters unsupported

252MDLP version unsupported

254Could not access the CDPD network

255Could not de-register the NEI because it was not registered

∙S-Register 57 (network status) - A bit-mapped register showing several items of interest. For error-handling the values of interest are:

∙ RF in range - value of 128 or greater (bit 7) ∙ Registered - odd value (bit 0)

∙ Connected - value of 133, 165, 197 or 229 (bit 2 and not bit 3)

∙S-Register 62 (connection failure) - This register indicates at what point in the operation the connection failed

1During the connection process

2During the transmission of a packet

3During the reception of a packet

∙S-Register 63 (connection failure) - This register indicates the most probable cause for the connection failure or loss of connection

24No socket available

67Address already in use

69Network is down

PN1197-00 Revision 1.0 8-5