Moxa SMG-1100 serial server

GPRS, EDGE, 2x RS-232/422/485, 144 x 119 x 40 mm, 1kg, -10 to 60°C, Antenna Length: 85 mm The SMG-1100 series features two software selectable RS-
232/422/485 ports, one Ethernet port, and quad-band GPRS/EDGE
900/1800/850/1900 MHz for cellular communication.
The SMG-1100 series provides a sophisticated wireless M2M solution
for distributed Modbus devices. The SMG-1100 networks Modbus
devices with Modbus RTU/ ASCII protocols can work well via GPRS/
EDGE or Ethernet to Modbus TCP, and each serial port can support
up to 31 serial slaves to IP network. Implemented with the protocol
conversion functionality, the SMG-1100 can serve both serial master
and slave and the built-in IPsec function guarantees that data
transmission is encrypted even in a wireless environment.