... 900/1800Hz, RS232 data, transparent data transmission,single data center or more, OverviewGPRS IP Modem is a data communication network terminal ... control, factories, mines data collection and monitoring, and other fields. W3100G/MMulti data center Cellular Module : ... or RS485 port, 15KV ESD protection;Maximum 4 data center Transparent transmissionMaximum 4 DNSKeep always onlineActive report ...