Product specifications

Features
3-6 80-99240-1 Rev. D
Packet/Asynchronous Data Overview
The GSP-1620 modem handles both packet and asynchronous
data connections. For a particular SCADA application, one
may make more sense than the other.
QUALCOMM Globalstar packet data service has a lower
overhead and faster connection time than asynchronous data
does. In general, if a SCADA application does not specifically
need asynchronous data, it should use packet data instead.
Table 3-1 compares the two types of data.
Table 3-1.
Packet vs. Asynchronous Data
Packet Data Asynchronous Data
Connects through a
Globalstar Gateway to the
Internet.
Connects through a Globalstar
Gateway and the PSTN to a
remote host modem.
Packet data is transmitted
over the Internet to a host
server.
Asynchronous data is
transmitted to a dial-up modem
or modem bank, which must be
supplied by the host.
Typically establishes
connection within 2-3
seconds.
Typically establishes
connection in approximately
30-60 seconds, due to modem
negotiation and training time.
No long distance charges
apply, because a connection is
made directly to the Internet.
PSTN long distance charges
may apply.
Degradation of service (in the
transmission of packets)
could occur, depending on
Internet connections and
routing.
Degradation of service could
occur, depending on the quality
of lines over the PSTN. (A noisy
PSTN line can lower the data
transmission rate or introduce
errors into the data stream.)
May require a VPN and
software to get past firewalls.
May be able to directly connect
inside a firewall.
Mobile-terminated calls
require either a fixed public
IP address, or a fixed private
IP address and VPN tunnel to
the Gateway.
Mobile-terminated calls can be
achieved by having the host
modem dial the phone number
of the GSP-1620 modem.