1.5.4.1                        Parallel Hard Key

Figure 1-11 Hard Key – LPT1 parallel port

The Parallel port version of the hard key is installed on a 25-pin parallel port (D25) on the SCADA node that adheres to IBM standards: LPT1 is supported.

Installing the Parallel Hard Key

To install a Sentinel Pro key, attach it to the parallel printer port of an IBM PC/XT/AT, PS/2, or true IBM-compatible computer. The side to be attached to the port is labeled ­COMPUTER­. Screws are provided to connect the key securely to the port.

If the computer is close to a wall or another obstacle, you can attach an extension cable to the port, and then attach the Sentinel Pro to the cable. Use a straight-through, 25-pin, male to female cable such as Rainbow Part Number 103027-001.

Incompatible Parallel Connectors

Some computers have a 14-pin connector. In this case, you can attach a Sentinel Pro key using an appropriate adapter cable.

Using Other Hardware Keys

Unlike the Sentinel Pro, some hardware keys “sit between” the computer and the printer. Such keys do not pass all signals through to the printer. If the Sentinel Pro is installed behind other hardware keys, it may not be able to communicate properly. For this reason, always attach the Sentinel Pro directly to the printer port, and attach any other security devices to the Sentinel Pro.

Interface Differences

If the computer’s printer adapter does not support the BUSY or ACK line, the Sentinel Pro cannot send data back to the computer as described above. This problem is very rare, as most IBM PC-compatible computers have compatible printer adapters. However, computers such as the Atari ST have the same connector and pin-out designations as an IBM PC, but lack the ACK line.

Handling Sentinel Pro Hard Keys

In general, the shipping and handling procedures suggested for the Sentinel Pro conform to the industry standards for handling electronic printed circuit boards. Your company may already have appropriate work areas and procedures in place.

Note:  Electrostatic charges may damage the Sentinel Pro units. Work surface mats and wrist straps are strongly recommended.