Sierra Wireless DART 200 CDPD Modem - Manual (Page 78)

DART 200 CDPD Modem User’s Guide 5 DART Supported Protocols
Sierra Wireless, Inc. 5-24
Automatic SLIP restart specifies that the DART 200 always enters SLIP
mode following power on or modem reset. It lets Winsock applications
rely on the modem always being in SLIP mode, particularly following a
power off/on cycle.
When this feature is active the modem is not in command mode
following power on. This can sometimes be inconvenient. Any time that
it is necessary to send AT commands to the modem, at initial application
startup or when querying modem status an escape function must be
performed (refer to &E or &D commands) before the modem responds
to AT commands. If using the manual escape function, check that both
the terminal emulation program and the modem are set to the same baud
or the escape will not work.
1. This capability is activated with an AT*R1 command (deactivate it
with an AT*R0). Bit 6 of S-Register 57 (value of 64) indicates that
auto slip mode is active. A modem that acquired a CDPD channel
(128), and used the auto registration feature (32) to get registered (1)
shows a value of 225 in S-Register 57 with Auto SLIP Mode Startup
(64) active.
2. Save the setting with the &W command to become a permanent
setting.
3. To make the command active, power cycle or reset the modem with
the AT-R command.
SLIP IP Address overview
• Internet Address Classes
CDPD Internet addresses are 32-bit fields consisting of a network ID
followed by a device ID (netid, devid). For readability, these 32-bit
addresses are broken down into four 8-bit fields (called octets or
bytes) that are then converted to their decimal equivalents and
separated by a period. For example, the address 11000000 00001110
10100111 00010101 (hardly readable) is represented as
192.14.167.21
Internet standards further define five classes of addresses, the first
three (A,B, and C) of which are used for network addresses.
• Class A addresses have a first octet between 1 and 127, and
consist of a one octet network address followed by a three octet
device address
• Class B addresses have a first octet between 128 and 191, and
consist of a two octet network address followed by a two octet
device address
• Class C addresses have a first octet between 192 and 255, and
consist of a three octet network address followed by a one octet
device address. Most CDPD addresses are class B or class C