Cellular modem applications tend to be more cost-
effective in locations where remote polling is problematic or placing a land line is impractical. A cellular modem
typically involves recurring monthly service fees and related expenses.
Wide area network polling
In a wide area network configuration, one machine is designated as the master unit and functions as a data transmitter. The master unit is capable of transmitting and receiving data from three to 10 miles, depending on topography. The master unit is designed to constantly search for slaves and other masters so an effective DEX data relay can be established.
If there is no local Internet connection, the master unit will pass its accumulated readings to the next master between it and the vending operator's warehouse. Depending on design, the warehouse may require an antenna.
Similar to other forms of polling, wireless polling enables remote access to DEX data via a network. Wireless polling, however, relies upon network connectivity to establish the proper linkage.
Many wireless methods of DEX transfer include file compression or filtering to reduce file size (i.e., the number of bytes transmitted) as a cost containment strategy. The advancement of wireless technology has emerged as an attractive alternative.
Wireless applications possess tremendous potential for the vending industry, an industry that desires mobility, flexibility and reliability in enterprise-wide operations.
Vending practitioners dissatisfied with the constraints and complexities of hard wiring are migrating to the convenience of design portability and user mobility that wireless technology solutions provide.
Data collection models
Several factors contribute to the viability of remote data collection and monitoring:
- Cost containment. Hardware and communication expenses (e.g., landline modem, wireless cellular modem and Ethernet cabling) have declined
as technology becomes more standardized and widespread.
- Interconnecting machines. Configuring a group of vending machines to form a bank, or block, capable of sharing a single point of connectivity minimizes expenditures.
- Integrated application software. Industry software suppliers have developed integrated remote monitoring software or have partnered with remote monitoring companies to form an integrated package.
- Cashless vending. Since cashless vending settlement involves a communication link to authorize payment processing, the same technology can be used to transport DEX data to a vending management software system, at little or no additional cost.
Remote DEX-data transmission typically is conducted at predetermined intervals (e.g., nighttime is usually preferred as polling may render the vending machine inoperable for 10 to 40 seconds during the process) and is dependent on sensitive connectivity prone to communication outages and damage or displacement by weather or vandalism.
Since most drivers use handhelds for inventory, product planogram changes and collecting additional data (like refunds and test vends) during the day, a majority of operators elect to continue using handheld devices despite the fact newer machines can be built with remote connectivity options.
One of the principal reasons vending management software utilizes DEX data is to control cash shortages and product shrinkage.
The table on page 36 summarizes a sample of available DEX data collection methods.
Activity/error reporting is an important DEX function because a large portion of the wireless vending benefit relies heavily on the timely reporting of activity and errors.
It is estimated there are many possible pieces of information that can be exchanged between a vending machine and a polling device; however, a set of eight are usually selected for transmission. The key variables are listed above.
A DEX file contains a set of vending machine transactions and event data. Stored data includes units sold by column, transactions by cash and credit, and various error codes measured in interval (since last reading) and cumulative metrics.
By comparing two consecutive DEX file readings, an operator can evaluate changes in cumulative totals.
In its raw form, DEX data is not immediately useful, and therefore, operators interested in developing meaningful DEX information typically expand the analysis to include: