User's Manual

Page 28

Connecting to the Computer

The Veri-Series units can be connected to the computer either through an RS-232

communications link, an RS-485 link, or via Ethernet.

RS-485 and RS-232 are hardware specifications and software protocol is not

specified. It is up to the system designer to define a protocol suitable for the

system. Bioscrypt has done this with the Veri-Series reader system. Detailed

information on the software protocol can be obtained by contacting Bioscrypt.

RS-232 communications with the Veri-Series unit use RX, TX, and GND connections.

The primary communications port is wired through the pig-tail in the rear of the

unit. There is also an auxiliary RS-232 port accessible from the bottom of the unit.

The RS-485 implementation in the Veri-Series uses a two-wire, half-duplex

communication configuration. In RS-485 there can be only one master and all

other units are configured as slaves. A master-slave type system has one node

that issues commands to each of the “slave” nodes and processes responses.

Slave nodes will not typically transmit data without a request from the master

node, and do not communicate with each other. Each slave must have a unique

address so that it can be addressed independent of other nodes. In the Veri-

Series reader system the computer is the master and the readers are each slaves

on the network. To connect the computer to the RS-485 transmission line, you

must either have a computer with a built-in RS-485 transceiver or use a converter

attached to the computer’s standard serial port (an RS-232 device). The cable

connection includes a differential line (+ and -) and a GND connection.

With the addition of the V-Station products, installations may now connect to

these readers via an Ethernet network*. Because Ethernet enabled devices like

the V-Station contain unique pre-allocated addresses, there is no need to have a

slave/host configuration. Communication collisions are automatically handled by

the low-level Ethernet protocol. However, the Veri-Series reader protocol is still

used on top of TCP/IP communications protocols. Therefore, a unique IP

addresses must be assigned to each V-Station reader, either through the

VeriAdmin software/LCD Menu or automatically from a DHCP server on the

network**.

In the event that you are connecting a single V-Station directly to the computer’s

Ethernet adaptor, a cross-over cable must be used and the following steps must

be taken.

Both the PC and the V-Station must have assigned IP addresses where the

beginning numbers match in accordance with the subnet mask used on the PC.

For example, if the subnet mask is 255.255.255.0, both the PC and the V-Station

must be assigned an IP address of A.B.C.x where A, B, and C are the same for