Logo: TUG TORONTO USERS GROUP for Midrange Systems
e -server magazine

March 1997: Volume 12, Number 4


By Randy Bunka

 Randy Bunka with Ed Jowett

oday's competitive marketplace is making manufacturers, distributors and wholesalers re-think warehousing practices. Growing volumes, space limitations and pressures from increasing customer demands (e.g. just-in-time delivery, accurate order status updates) are timely issues being addressed by businesses. Business professionals know the value of accurate and timely data. If information is incomplete or inaccurately input, productivity and operating efficiencies can drop. Bar Coding and Automated Data Collection Systems are proven methods of improving productivity, eliminating unnecessary or overlapping procedures, enhancing control over operations, tracking production and distribution of products and providing accurate company records.

Areas where these technologies have been successfully applied include Inventory tracking and Control systems, Production, Labour and Asset tracking, Conveyor control and Sortation, Weigh scales, Portable data collection and Field support for fleet operations and Work in process tracking.

5250 Emulation

5251 terminal emulation uses an intermediate communications processor platform, an RF controller and 5251 terminal emulation software to emulate the operation of remote 5251 terminals in an IBM SNA/SDLC environment. In this type of system, portable hand held units replace stationary 5251 terminals. These units can be taken to the location where work is being done and real time data can be gathered and transmitted. Existing 5251 applications can run on the RF system without alterations (except for screen size) and the system can easily be upgraded as processing needs expand. To the host computer, each hand held looks like a standard 5251 Model 11 terminal. The RF controller/base station uses SNA and 5251 data streams to transmit data between the host, RF controller and hand held.

In a typical SNA 5251 environment, the 5251 terminals are connected to a cluster controller by twinax cable. The cluster controller connects, through modems or modem eliminators and a communications controller, to the host computer via a channel. Such a configuration limits the placement of terminals in the facility and usually requires that an operator collect data in one location and, then, take it to the terminal where it is manually keyed in and transmitted to the host.

The key element in an RF system is the RF controller which is connected serially to the AS/400. The AS/400 is then configured to recognize the presence of a 5394 cluster controller which is, in fact, the RF controller. Each hand held device receives its own unique name and is attached to the appropriate subsystem. Within the configuration of the RF controller, each hand held device is cross referenced from its own unique RF ID# to a LU number. For example, RFID #001 is set to LU 001.

When both the RF controller and the AS/400 are properly configured, the serial line connecting them is initiated by varying the line on/off. A session on the hand held is then initiated by selecting "start emulation". The hand held will communicate with the RF controller by sending its RF ID#. The RF controller performs a cross reference to the AS/400 setup parameters. Once the communication link is established, the appropriate log-in screen is sent to the hand held.

Screens sent down to the hand held must fit on the unit. Otherwise, the operator will have to use the cursor keys to scroll around. The standard IBM 5251 terminal display has a capacity of 1920 characters. The RF hand held screen, through its advanced screen mapping capabilities, can map all 1920 characters. Depending on the setup, the hand held screen can show between 15 to 40 percent of the 5251 terminal screen display. Thus, the first field displayed on the hand held centers around the first unprotected data entry field. If the operator wants to enter data elsewhere, scrolling is necessary to locate the required field. For this reason, all necessary prompts and fields should be designed and set up to fit within the area of the selected display. Also, multi-page inquiry screens should not be used in an RF environment.

While the "fortunes" of the RF system are tied to the AS/400, the benefit of this type of solution is a real-time, seamless interface between the two systems. This type of integration can provide significant savings in time and costs. The reliability of AS/400 systems provides an advantage in this area. Another advantage is that the user has control over all the applications that are displayed on the hand held and changes can be incorporated quickly, often without any additional costs. The source code is written and owned by the user. This gives the user the ability to plan, or quickly adapt to, changes and additions in the use of the system without having to depend on specialized expertise from outside sources.

The value placed on accurate and timely data is high for any warehousing environment. This real time solution for the AS/400 will allow businesses to address key issues relating to improving customer service, management reporting, employee productivity and operating efficiencies. The use of radio frequency equipment in industrial and retail settings is growing at a rapid pace due to its improved performance, decreasing costs (as compared to wide area wireless technology) and emerging industry standards. Warehousing businesses can therefore expect to gain a definite strategic and competitive edge against their competitors by choosing to unite their AS/400 to the RF network. T < G