BackPowering devices through bottom ports
9 Jun 2014
Note: This information is provided as a reference and does not imply that Juniper Systems will provide full support for the use of any specific third-party hardware or software with a Juniper Systems product.
Devices which had been customized to be powered through the COM1 port pin 4 Data Terminal Ready (DTR) line on our previous model products can continue to be powered through COM1 on the Allegro 2 or Archer 2 by creating or purchasing an adapter cable (such as our part number 24938) as well as installing the "A2-Enable-Power-On-COM1.CAB" patch file below.
For other devices, the rugged handheld computer can power external devices (such as sensors and scanners) through the bottom serial COM port and/or the USB Host port. Standard 5V output is provided on the USB Host port. The serial COM1 port can provide a separate 5V output on the pin 9 Ring-In (RI) line after populating the following Windows registry key then soft Reset.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn\Serial_1]
- "LinkRI"=dword:0 (binary 0000)
Bit0: = 1
- { 0 = RI power is only controlled by JSAPI}
- { 1 = RI power can be controlled by Serial driver (see bit1)}
Bit1: = 1
- { 0 = RI power is enabled/disabled in COM_Open/COM_Close}
- { 1 = RI power is enabled when DTR asserts, disabled when DTR deasserts (bit0 must =1 for this bit to have any affect)}
Bit2: = 0
- { 0 = RI power is always off during suspend}
- { 1 = RI power maintains current state during suspend}
Bit3: = 1
- { 0 = USB Host IO power is independent from user control}
- { 1 = USB Host IO power matches RI power state}
An example is if LinkRI = decimal 3 (binary 0011, reflecting Bit3 through Bit0 in that order), it will behave similar to our previous products which track the state of the pin 4 DTR line. The following file patch can potentially enable this for you if desired. Click on the file link below to download/save the file, copy (do not extract) the file to the handheld, and then locate and tap on the file name in File Explorer on the handheld to install.
Each power supply (on COM1 and USB Host) can individually separately deliver up to a little over 3 watts (5V @ 600 mA) of power.
A custom 12V I/O module can be provided which combines these power supplies into one by removing the USB Host port (leaving only COM1 with output on pin 9) and converting the output from 5V to 12V DC up to 6 watts (12V @ 500 mA) current draw. The LinkRI registry must be set to decimal 11 (binary 1011) to track the DTR signal state, or decimal 9 (binary 1001) to just track the open state of the port. For more information on this optional I/O module, please contact sales@junipersys.com.
For similar information on previous or legacy products, please refer to this web page.
