AT+i Programmer's Manual - SE Spezial-Electronic AG
AT+i Programmer's Manual - SE Spezial-Electronic AG
AT+i Programmer's Manual - SE Spezial-Electronic AG
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iChip RAS Server<br />
iChip defers to PPP negotiation. The (~) is the last character transmitted to the host end to<br />
signal that iChip has taken over the negotiations. Upon this event, iChip continues to<br />
negotiate a PPP connection internally in a manner similar to the procedure that occurs<br />
when iChip picks up the line after receiving RING strings. If, however, the first<br />
character received from the calling end after the CONNECT line is not a (~) (0x7E),<br />
iChip remains in Transparent mode, and a regular modem-to-modem data session takes<br />
place.<br />
27.3.2 SerialNET Mode<br />
The RAS can also be enabled while iChip is in SerialNet mode. In this case, however, the<br />
modem RING strings are not forwarded to the host serial port. Once the PPP connection<br />
is established, iChip proceeds to act as it would after receiving a RING event and creating<br />
a PPP connection to a remote RAS server. That is, a listening socket is established on the<br />
LPRT socket, available for a SerialNET connection. This provides an alternative means<br />
to wake-up a SerialNET server device.<br />
27.3.3 Lost Carrier<br />
When iChip is online as a result of a RAS connection and the carrier signal is lost (due to<br />
an error or due to the PPP client closing the connection), iChip checks if the host used the<br />
PPP connection (tried to open an Internet session) during the connection. If the host did<br />
not use the connection, or iChip was in SerialNET mode, iChip silently performs a<br />
software reset and no indication of the disconnection is given to the host. Otherwise, if<br />
the host did use the connection, iChip acts as if this is a regular session created by the<br />
host that was terminated with a lost carrier signal. The error code is returned to the host<br />
on the next command that requires the use of the connection and only then will a software<br />
reset be performed.<br />
27.3.4 Restrictions<br />
Modem RING strings are not detected while the baud rate between iChip and the host is<br />
not yet established. This means that in order to use the RAS feature, one of the following<br />
must apply:<br />
BDRF is set to a fixed value (3-9 or h).<br />
iChip is in SerialNET mode with its baud rate defined by the SNSI parameter.<br />
An a or A was previously received from the host serial port and iChip has determined<br />
the host‘s baud rate.<br />
In addition, Modem RING strings are not detected when iChip is in Modem Command<br />
(MCM) mode.
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