USB to Serial Converters Manual
Version 2.0
Document Reference No.: CP_000032 Clearance No.: CP#022
Copyright © Connective Peripherals Pte Ltd
30
Jumper
Function
1 - 2
Enable Tx+/- Termination with 120 Ohm. This jumper should be populated for RS-
485 half-Duplex mode
3 - 4
Pull-up Tx+ to VCC by 750 Ohm Bias resistor. This jumper should be populated to
enable pull-up of Tx+
5 - 6
Pull-down Tx- to GND by 750 Ohm Bias resistor This jumper should be populated
to enable pull-down of Tx-
7 - 8
Enable Rx+/- Termination with 120 Ohm. This jumper should be populated for RS-
422 and RS-485 Full-Duplex mode
9 - 10
Pull-up Rx+ to VCC by 750 Ohm Bias resistor. This jumper should be populated to
enable pull-up of Rx+
11 - 12
Pull-down Rx- to GND by 750 Ohm Bias resistor. This jumper should be populated
to enable pull-down of Rx-
13 - 14
Enable CTS Termination with 120 Ohm. This jumper should be populated for RS-
422 mode.
Table 9 - Jumpers to select Termination and Biasing
Note:
If biasing of an RS-485 half-duplex bus is required, enable Rx biasing only (Pull-up Rx+ to VCC by
750 Ohm Bias resistor and Pull-down Rx- to GND by 750 Ohm Bias resistor). Tx biasing should not be used
as this would provide two sets of biasing resistors on the bus. See the notes in section 5.1 before setting
Termination and Biasing
5V Power Enable Jumper (ES-U-3001-MB and ES-U-2101-MB)
The ES-U-3001-MB and ES-U-2101-MB can supply 5V (at up to 150mA) through Pin 5 of the terminal block
to allow external devices to be powered. To enable the power, you need to open the metal case and set
the jumper (JP2) to the position of “ON”.
Jumper
Function
ON
Enable the 5V 150mA output on pin 5 of the Terminal Block to provide
power for external devices
OFF
Disable the 5V 150mA power (Default)
Table 10 - Jumper to select 5V output
RS232 Pin-Out (ES-U-2101-MB)
The ES-U-2101-MB has only a subset of the signals on the DB-9 connector to provide TxD, RxD, RTS,
CTS and GND. The pinout can be found in Table 12.
