Hybrid modes, Tcp auto answer – Sierra Wireless 20070914 User Manual

Page 83

Data Communication and Host Modes

Rev 3.0B Feb.08

The TCP session will be terminated if no data is transmitted or
received for the time interval specified in TCPT and TCPS.
TCPT is the number of minutes (TCPS=0) or seconds (TCPS=1)
used for this idle time‐out.

Caution: TCPT should never be 0 when using the TCP mode. A
broken TCP session can result in the modem being left with a TCP
half-open connection that can only be terminated with a reset.

TCP Auto Answer

TCP auto answer (S0=1|2) also allows a TCP connection
request to be “answered” when the modem is idle, not in a
data session. The TCP connection requestʹs destination port
has to match the modemʹs device port.

Note: UDP auto answer may also be set simultaneously with TCP
auto answer. Then, when in the idle state, the modem will accept
either a TCP connection request or UDP incoming packet, and enter a
TCP or UDP session as appropriate.

Hybrid Modes

Hybrid modes are supported mainly for legacy implementa‐
tions. Some previous hybrid modes (MD=5, 6) are no longer
implemented as special, unique modes. Now that UDP auto
answer (UDP Half‐open, S82=2) can be enabled in conjunction
with UDP PAD mode (MD3), effectively this is the same as
MD5 and MD6 previously accomplished. Setting MD5 and
MD6 are still supported, but not recommended.

AT Command

Hybrid Mod

(MD5)

Hybrid Mode2

(MD6)

S82

*UDPLAST