DEX and MDB: A Primer For Vendors

Two of the most oft-mentioned and misunderstood technologies in our industry are MDB (multi-drop bus) and DEX (digital exchange). It amazes me how frequently I hear people confuse MDB and DEX, as if they are related. Allow me to end that rumor right here. The only correlation between DEX and MDB is that they are two separate and distinct technologies that happen to reside in modern day vending machines.

DEX BRINGS IMPROVED AUDIT

DEX was brought to the industry in the late 1980s to provide better audit capabilities. The bottlers brought DEX, a uniform commercial code set up across many industries, to vending when they implemented DEX for communications between a route handheld and a grocery store’s computer system. Since many bottler route drivers performed direct store delivery (DSD) as well as service of can/bottle machines, it made sense for their handheld to communicate with the vending machines they serviced as well as the stores. As often happened due to their size, resources and commitment to implementing technology, the bottlers took the leadership position, and the National Automatic Merchandising Association Technology Committee (made up mostly of engineers and industry suppliers) followed suit, adopting DEX as our industry standard.

VENDING USAGE INFORMATION

So what is DEX? DEX is our standard for an ASCII code-based electronic audit file, a way to communicate information such as sales, cash in bill validators, coins in coin boxes, sales of units by selection, pricing, door openings, and much more. It is created either locally by the VMC (Vending Machine Controller often called the “brain” of an electronic machine) or created by a retrofit DEX device in older electromechanical (dip switch) machines.

DEX is the result of the VMC storing information on an interval basis (the interval of time since the last DEX reading) and cumulative basis (since the VMC was first installed or the machine went into service). The VMC accumulates the data and transmits it in DEX format (see sidebar) over the DEX port when requested.

DEX data is quite useful and extensive. It eliminates the need for route people to write what they loaded into a machine on a route card. It also makes it unnecessary to manually input this information into a handheld. But the feature of DEX that gets most companies excited and starting to “DEX” their machines is the accuracy of cash accountability. There is no more second guessing what was to be collected out of the machine.

DEX IMPROVES ROUTE ACCOUNTING

DEX data is downloaded to a handheld device or transmitted via a remote monitoring device over to software that can parse the information into useful reports. DEX is downloaded using a 0.25-inch stereo plug (exactly like the one with your old stereo headphones from the 70s). When downloaded to a handheld, DEX is parsed and compared to planogram information unique to that machine that was stored in the handheld. This informs the route driver how many units of each product he/she has to load back into the machine to bring it back up to par.

Remote monitoring devices (wireless, LAN or telephone) can forward DEX, usually via the Internet, to a central computer where the software performs the same tasks as the handheld, but from the headquarters. This gives vendors the opportunity to pre-assemble items for locations before drivers leave and efficiently pack route trucks with only the necessary products.

Approximately 60 to 70 percent of the machines currently deployed have “native” DEX, meaning the machines come with a VMC that produces DEX. Sometimes a newer version of firmware for the VMC and a DEX download cable are required to be added to enable DEX.

Older electronic and electromechanical machines not equipped with DEX can be retrofitted with either a new VMC that provides DEX (and many of the features found in new machines) or with a retrofit DEX audit device.

DEX File Interpretation Chart - View this chart in PDF format.

MULTI DROP BUS RELATES TO PAYMENT