System shell

Any QNX-based JACE has a “system shell,” providing low-level access to a few basic platform settings. Using a special JACE power-up mode, you can access this system shell using a serial connection to the JACE’s onboard RS-232 port. Note that system shell is also available via Telnet (providing that Telnet is enabled in the JACE).

Typical usage is for troubleshooting. However, in the case of IP address mis-configuration, you can use the serial system shell in order to regain access to the unit.

Also, depending on your preference, as an alternative to reconfiguring your PC’s IP address in Windows (to initially connect to a new JACE), you may wish to use the serial system shell to set the JACE’s IP address. If done as the first step, afterwards you could connect normally (Ethernet/IP) and perform all other Niagara software installation/platform configuration using Workbench and the Install Niagara R2 wizard. This method would save you from having to re-configure your PC’s IP address settings in Windows: first to connect to the JACE as shipped from the factory, and then back again to its original settings.

The following sections provide more details:

About JACE serial shell mode

Any JACE circuit board has a small 4-pin jumper header, commonly called the mode or “Serial Shell” jumper. To put the JACE in serial shell mode, you put a 2-pin jumper block on certain connector pins, and cycle power to the unit. Upon system boot, this makes the system shell available at the JACE’s primary RS-232 (COM1) port, at a pre-defined serial rate (for the NPM6E processor, this 115200, 8, N, 1).

Using a serial terminal program such as Windows HyperTerminal, you can then login using platform credentials and access the system shell menu. After changing platform IP address parameters, a reboot command from the menu is necessary, and you remove (or reposition) the mode jumper. The JACE reboots using the changed IP address parameters, and its COM1 port operates as normally configured.

If using COM1 for any other application, be sure to remove the 2-pin jumper when rebooting from the serial system shell.

Items needed for serial system shell

Apart from physical access to the JACE, you need the following items:

A working RS-232 port on your PC.

Usually this is a DB-9 connector with a specific Windows ComN assignment (say Com1 or Com2). However, newer notebook PCs may require a USB-to-RS-232 adapter, installed with a Windows driver.
Terminal emulation software, such as Microsoft HyperTerminal (standard Windows app).
A serial cable to connect between your PC’s serial ComN port to the JACE’s RS-232 port, plus any adapter, if necessary.

For a JACE-603 or JACE-645 that has one or more RS-232 ports that use RJ-45 connectors, the following parts, listed by Tridium part number, apply:
- 10148 — Adapter, RJ-45 to DB-9, null modem type
- 10181 — Silver satin RJ-45 patch cable, 10 ft. (connects adapter to RJ-45 type RS-232 port)
  
  Patch cables are also available in lengths 4 ft. (10180) and 25 ft. (10182)
A 2-pin jumper block for the JACE’s “Serial Shell” jumper pins—this should already be installed on the “Normal” position pins.

Using serial system shell

The following procedure provides steps to use serial system shell.

To connect to the JACE serial system shell

To connect to the JACE’s system shell using a serial connection, do the following:

Connect the necessary serial cable and adapter between the JACE’s RS-232 port and the RS-232 COM port you are using on your PC. See Items needed for serial system shell.
On your PC, start HyperTerminal. From the Windows Start menu, this is typically Programs->Accessories->Communications->HyperTerminal.
In the “Connection Description” dialog, type a name for this session.

For example: Jace serial shell

Click OK.
In the “Connect to” dialog, use the “Connect using” drop-down list to select the COM port you are using on your PC, for example COM1.

Click OK.
In the Comn Properties dialog, choose the following settings:
- Bits per second: 115200
- Data bits: 8
- Parity: None
- Stop bits: 1
- Flow control: Hardware
Click OK. The HyperTerminal session is now set up.
On the JACE-603 or JACE-645 circuit board (NPM6E processor), locate the 4-pin jumper header and put the 2-pin jumper block on the two “Serial Shell” pins. See the label on the board’s NPM6E processor.
With your HyperTerminal session active, remove power from the JACE, let it cycle down, then reapply power.

After some number of seconds, text should appear in the HyperTerminal window similar to:

Press any key to stop auto-boot...
Do not press any key, wait for the login prompt.

If you did press a key to stop auto-boot, select option 1 (Boot from on-board nand flash).
At the login prompt, enter the platform user name, and at the password prompt, the platform password. See Platform daemon credentials for factory-default values.

The system shell menu appears. See About the JACE system shell menu.
When finished making platform changes from the serial system shell, do the following:
- Move the 2-pin jumper block from the “Serial Shell” position back to the “Normal” position.
- From the system shell menu, select the Reboot option.
  
  Type “y” at the “Are you sure you want to reboot [y/n]” prompt, and press Enter.
  
  Shutdown-related text appears in the HyperTerminal window, and then the connection is dropped.
Press the Disconnect button on the HyperTerminal tool bar.
Exit from the HyperTerminal application, selecting to Save if you wish to reuse this setup again.