4-Port RS232/485 to RS-485 Hub/Splitter/Repeater with 15KV ESD Protection

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The SER-4485-SI-M is an industrial-grade RS-232/485 to optically isolated 4-port RS-485 repeater/splitter/hub. This RS-485 hub is designed to expand a RS-485 channel in the RS-485 network to four RS-485 channels. It has one RS-232/RS-485 upstream input port and four independent downstream RS-485 output ports. Data received from the input channel will be simultaneously transmitted to all the four downstream RS-485 channels. Data received from the downstream RS-485 ports is forwarded back to the upstream port only, and is not sent to any other RS-485 ports in the loop. Each RS-485 output port is designed with an individual driver. The failure of any RS-485 ports in the downstream loop will not affect the normal function of the other RS-485 ports to ensure reliable operation.

The SER-4485-SI-M 4-Port RS-485 hubs can be added to RS-485 network to increase the maximum nodes up to 512 nodes of RS-485 devices and to increase the transmission distance more than 1.2km with stable and reliable performance.

The SER-4485-SI-M is optically isolated with 3000VDC optical isolation. The optical isolation protects your PC or RS-485 devices from spikes and surges on the RS-485 network, by converting the electrical pulse into an optical signal and then changing it back into an electrical pulse. Your computer or related RS-485 device is well protected, since the surges and spikes cannot cross the optical link. The SER-4485-SI-M is protected by surge protector to withstand electrostatic discharge and power surges up to 600W. Surge suppression on all signals prevent from damages caused by lightning or high voltage.


  • Industrial-grade 4 port RS-485 hub/splitter/repeater with rugged metal case
  • Isolates and protects RS-485 devices from a RS-485 bus
  • Electrical isolation up to 3000VDC from RS-485 upstream port to RS-485 downstream port
  • Suitable for DIN-rail mounting
  • 600W surge protection circuit on all RS-485 bus (downstream and upstream ports)
  • RS-232 and RS-485 input interface options
  • Supports transmission data rate up to 230.4kbps
  • Provides failure warning and protected circuit for four RS-485 downstream ports
  • LEDs for power, communication and error status indication
  • Input power connector with screw holes to lock the power cable
  • 12VDC power adapter included
  • With diode bridge circuit to avoid wrong polarity input DC power
  • Wide ambient temperature operation 0°C to 60°C (32°F to 140°F)


PortsInput (upstream)1 RS-485 port (Data+, Data-) or 1 RS-232 port (TxD, RxD, GND)
Output (downstream)4 RS-485 ports (Data+, Data-)
Transmission Media2P twisted-pair or shielded cable
Transfer Distance1.2km at 9.6kbps 400m at 115.2kbps
Max. Devices Supported128 devices each channel
Speed300bps to 230.4kbps
ESD Protection15kV
Connection6-pin terminal block for upstream 10-pin terminal block for downstream
LED Indicators
LEDsPower1 (PWR, Red)
 Port Status2 (TxD: Green, RxD: Yellow)
 Error Status4 (Err1, Err2, Err3, Err4: Red)
Input Power RangeDC or AC +9V~48V
Power Consumption1.5W (max)
HousingRugged metal case
Dimensions62mm × 93mm × 24mm (W × L × H) 85mm × 93mm × 24mm (W × L × H) with DIN-rail ears
Operating Temperature0°C to 60°C
Storage Temperature-40°C to 85°C
Humidity0 to 80% RH. Noncondensing


Product Manual