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Point-of-Sale Integration. Are they buying what youíre selling?

POS integration (or till Interfacing) provides the ability to extract the data from a till that prints on the receipt and overlay this data on a video picture of the check out area. Most front end cameras are positioned to see the cashier, the cash drawer, items purchased and the customer. With all these elements recorded on tape, a store owner can review this scene and with one view verify the check out was legitimate.


How an Interface Stops Theft

The till interface as an overt (clerks and customers know the interface is in place an how it works) security system can deter theft by the fear of being caught along with a permanent record. This system as a covert (hidden system) will not prevent the theft but will record the event for later prosecution.


n either case, the till interface system will allow the recording of all transactions for later review for such thefts as sweethearting, substitute scanning, no rings, short changing, short rings, and pilfering.

Types of POS Theft

Sweethearting - This requires an accomplice or sweet heart that loads up expensive items for check out. The clerk then either does not ring up certain items or rings up the items but charges a lower price than marked. This type of loss shows up later as inventory shrink.

Substitute Scanning - This is usually a type of sweethearting that is done in stores that have scanning systems. The clerk fixes a scan tag of a low value item on their palm. When an item is scanned, the palm tag is read and not the actual item. Substitute scanning can also be done without a sweetheart. The correct value of the sale is collected from the customer and later pulled from the till near the end of the shift. This type of theft if viewed by a convention camera system looks like the clerk was ring correctly, but with the text overlay, the manager can instantly see the substitute scan.

No Rings - This is where a clerk rings nothing up and makes change from an open cash drawer or from the top of the change drawer.

Short Changing - This is where the clerk is actually cheating the customer by giving incorrect change.

Short Rings - This is where a clerk rings up an incorrect amount for an items much lower than the actual value and either immediately pockets the extra money or pulls it from the till later. Usually the clerk does not complete the sale until the customer leaves. This is because if the customer asks for a receipt or challenges the price, the clerk can cancel the entry and ring up the correct on.

Pilfering: Is taking money directly from the till and leaving the till short. This usually occurs when more than one clerk uses the same cash drawer.

Exception Reporting

As described above most of these theft practices require the ringing up of substitute or low value items or opening the drawer without a normal sale. These types of till transactions are called exceptions. A till interface can electronic watch for these types of questionable transactions and give a signal when detected. This signal can be in the form of an on-screen flag or alarm a VCR for later search or automatically turn on the camera watching that till and clerk. The most common type of exceptions monitored are no sale, voids, returns, refunds, cancels, purchases, payouts, low value sales and high value sales.

No Sales - This is the most common exception. Some legitimate uses are making change or correcting change mistakes. The No Sale is always a questionable transaction. Towards the end of a shift, whether the clerk was doing short rings or any kind of pilfering, will have to remove the accumulated money for that shift. All No Sales should be exceptions, and all in the last hour of a shift should be reviewed.

Voids - The void is used after the customer has left and the same transaction has been voided. The money is still in the till and will have to be removed either then or towards the end of the shift.

Returns/Refunds - This is usually questionable when no exchange is being made and cash is paid out. Items are pulled from inventory and fictitious refunds are given to one self, the clerk or a sweet heart.

Cancels - This is where a transaction is partially rung up. The clerk asks the customer for the money and if the customer does not ask for a receipt and leaves, the clerk cancels the sale. If the customer wants a receipt then the clerk finishes the transactions and gives the receipt.

Purchases or Payouts - This is usually in small convenience stores when they receive papers, or other non account deliveries. The clerk rings a payout and gives the vendor cash. The clerk can be in kahouts with the vendor and overpay and later collect or simply make the pay out for more and keep the difference.


Pre-Exceptions or Post Exceptions

There are two schools of thought on exception monitoring. The pre-exception technique is usually for low cost situations and is most common. This is were the exception is programmed into the text inserter and it gives an alarm when the exception is detected.

The post exception systems record all the data from all tills in an electronic file. They also will store either only the exceptions when using Pan/Tilt cameras or all the video data with fixed cameras and multiplexers from all the tills. At a later date the store owner can search the database for any type of exception he may think of later. He will then have to go to the tape at the time and watch the exception. Some sophisticated POS systems actually match this database with the correct piece of video automatically.

How Till Interfacing Works

The till business is a unique industry in itself. There exist no standards, as a matter of fact, till companies go out of their way to make hardware different. This is true from company to company and even true within a company so older accessories are not compatible with the newer models. It is this fundamental fact that makes till interfacing such a complicated problem. One interface box can only connect to an extremely limited number of tills. The use of converter boxes are needed to translate from one format to another. Every model till has unique features that enhance the interface or cause major problems when dealing with loss prevention.

Typical Till Interface

All till interface systems must contain a Text Inserter to do the text overlay on the video picture. This main box also has communication channels that can plug directly to some till without the need for other converters. As stated above the number of direct connections is limited and in most applications the need for a converter box is warranted. These converter boxes are almost always placed in or near the till. Data cable is then run from the till location back to the security room to the text inserter. The text inserter and other security equipment are then centrally located.

Till Interface Outputs

Alarm Outputs - The alarm output option gives hard alarm outputs to go to VCRs to flag the tape for later search. This alarm can control a switcher to home a camera in on the till when certain type of transactions are detected.

Printer Outputs - Most till interfaces have serial printer outputs. This output is usually configured to print a list of the detected exceptions. At the end of the day, the store manager can review the exceptions of the day or night before and decide whether to view the tape or not. Other uses may be to connect to a PC and record all the transaction or go to modem to download the exceptions in the middle of the night to central.

On-screen Messages or Flags - Usually when a till interface detects an exception it also highlights or some how marks the video picture. This allows easy review of the exceptions in forward scan mode or alert a manager during operational hours.

Network Interfaces - When POS systems have many terminals they are usually connected together through a network of some sort. Most of these networks can be monitored and the data from any till can be overlayed on the video picture. Usually the data on networks is not live (does not happen exactly when the clerk rings up the sale) to save network time. Although it is usually live enough to monitor for exceptions or make an alternate electronic journal. The advantage of this type of interface is that the data from all tills is available to one text inserter. This inserter in conjunction with a matrix switcher allows monitoring of any till throughout the store.

POS Interface Networks - When live data is required for the text inserter, an interface must be put at each till and thus configured into a network exclusively for the till interface. This is effective but still has limitations and advantages of the POS networks in some much it usually only monitors one till at a time in video.

How Tills Communicate - The following are brief technical explanations of the most popular types of methods that till interfaces communicate to tills.

Serial Communications - Serial communications are simply a series of voltage or current changes which are translated into the binary equivalents of 1 or 0s. After a series of this data is received, the computer reconstructs the serial data into its original binary format for computation.

Asynchronous - Asynchronous communications or simply assync , is usually called RS-232 communications. This generic RS-232 terms is over used because there are several types of asynchronous communications broken into electrical formats and/or protocol format. All assync communications consist of a pre-defined baud rate, a start bit, a defined number of stop bits and parity which determine the number of bits sent per frame or data packet. Standard RS-232 communications is most common in your home computers COM1-COM4 ports on the back of the computer.

These ports connect to the mouse, modem or serial printer. RS-232 uses voltage swings from +12VDC to -12VDC to denote the transmission of 1s or 0s. RS-422 is similar in format to RS-232 but uses current pulses to denote 1s or 0s. This is typically a 4 wire system.RS-423 is similar to RS422 but uses isolated grounds between the TXD and RXD channels for noise immunity.RS-485 is a current technique that utilises current flow in the forward direction as a 1 and reverse current as a 0. This is normally a 2 wire system.High Speed interprocessor communications are used for short distance applications. These techniques very from microprocessor manufacturer but range in baud rates from 38K to 387K typically.

Synchronous - Synchronous data usually consists of a Data signal and a synchronous clock signal. With this format the baud rate is defined by the synchronous clock. The data stream is searched by byte by the receiver device and when the sync byte is detected the received is said to be in sync. At this type the receiver reads each successive byte to decode the proper data. This type of data is packetised, which means a sync byte heads up a certain amount of data.

Bisynchronous - Bisynchronous communications is very similar to synchronous, but varies in the protocol and packet information. This format has to detect two successive sync bytes or one word, for the stream to be in sync. The popular names for this format is 3270 or 3275.High Speed interprocessor communications can also be synchronous or bisynchronous. This is similar to the high speed assync method but the use of an external clock signal and sync bytes are used. This data rate can range from 38K to 10Mhz typically.

SDLC - Synchronous Data Link Communications (SDLC) is a high level communications technique that combines all of the above techniques. SDLC can contain high level protocol with multiple header and data identifiers. This format is similar to synchronous communications but searches the data stream bit by bit to identify a sync byte or word. Again this format is packetised with sync bytes and can contain packets from many sources and destinations.

NRZ/NRZI - None Return to Zero (NRZ) or None Return to Zero Inverted (NRZI) are common protocols for SDLC. These formats contain a separate clock signal for each data channel. Their electrical format is +12VDC to -12VDC similar to RS-232.

NRZId - None Return to Zero Inverted Derived Clock (NRZId) has the clock signal electrically embedded in the data signal. The receiver must lock on to this clock to generate the proper baud rate to read the incoming data stream.

Manchester Encoding - This encoding technique also has the clock embedded in the signal and must be split apart.

Parallel - Parallel communications format presents data in a parallel format to the receiver and then strobes the receiver when the data is ready. The receiver reads in the data and processes it. This format is faster than serial since more than one bit is transferred per clock signal.

8 Bit - The most common parallel technique is the Centronics format. This is what every PC uses to talk to the LPT or printer port. Eight bits or one print character or control code is sent at one time. Some proprietary variations of this format are used for other printers, customer displays and general communications.

4 Bit - This technique is similar to the 8 bit but only 4 bits are sent at a time. To get one ASCII character, two transfers must occur. This format is also used for send numeric values only which can be describe by on 4 bit nibble.

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