Integration. Are they buying what you’re 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
How an Interface
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.
In 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.
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
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.
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.
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.
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.
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.
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.
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
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.
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.
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
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
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.
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
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
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