Frequently Asked Questions - POS
Q: This particular merchant runs Windows. I don't think they have a pole display, though I can check. Ideally, it would be great to accommodate, with or without pole display. If it runs better on Linux, going forward I would propose Linux workstations for new merchants.
Ok. Let's first explain what the problems we have to solve are, then discuss the solutions that are bundled.
In general web browsers are engineered so that malicious sites can't access your computer's hardware. In general we don't want to change the browser (for example with an add-on) to make it do this because there might be a capacity for abuse elsewhere. So things like receipt printers, pole displays, cash drawers, and barcode scanners cannot be directly be accessed by the browser. This makes a web-based point of sale rather challenging, but we have solutions to these problems. The solutions though are only tested on Linux. On Windows they will require slight modification and I would recommend some extra testing. Backup/fallback methods are discussed below as well.
What we do instead preferably is to turn the point of sale terminal into a server for the point of sale hardware. Scripts to do this (written in Bash) are in the utils/pos directory of the LedgerSMB installation. the client-side script is pos-hardware-client-startup-script which basically fires up netcat and listens for data to redirect to a hardware port. You probably want to use firewall software to limit this traffic to approved servers. The ports are configurable on both ends. On the LedgerSMB side, see the pos.conf.pl.
The other is directnet.pl which is used to send printable documents over this (and to the POS printer on the other side). This is designed to be a low-latency alternative to using CUPS and the like. It redirects pole display logic usually to a serial port, and the printer logic to a parallel port.
This means you can use any printer that accepts ESC/POS and it will send signals to open the cash drawer (programmable in the pos.conf.pl) if the cash drawer is the kind that plugs into the printer. You can also use a pole display although currently we only have drivers for the LC3000 by Logic Controls. The drivers are really easy to write though. Feel free to ask for help or contribute one.
Barcode scanners and magnetic stripe readers need to come into the computer as keyboard input. Typically this means a keyboard wedge interface for magstripe readers, and either a keyboard interface for a barcode scanner, or a barcode scanner attached to a POS keyboard with a built-in barcode decoder. I have had better luck with the latter in terms of long-term maintenance, but they both work.
On to the pos.conf.pl. The default values here are in the pos.conf.pl.template, so please cp pos.conf.pl.template pos.conf.pl
For the miost part this defines a single variable for storing the information called $pos_config. Keys for this and their significance are:
rem_host: Remote host to send pole display/printer info to. By default this is the remote host. However if you are running X11 applications remotely you may have to change this.
pd_host; Host for the pole display. Defaults to rem_host
pd_port: Port for the pole display. Defaults to 6601
pd_proto: Protocol for pd. Either 'tcp' or 'udp' defaulting to udp.
Same as pd_* above but for printer
rp_cash_open: The code to open the printer. Defaults to those for the Epson U220D iirc, which is binary string of values 27, 112, 0, 25, 250
coa_prefix: prefix for the till amounts. If you have a till '16' and a coa_prefix of 1300, the till account will be 1300.16. This account must exist or you will get errors.
close_cash_accno: Cash account to put closing cash into. Must exist by closing time.
$pos_sources is used to define memo fields for different types of payment. You can customize this as you want.
$pos_source_default is the default for the sources drop down.
curren is the currency
breakdown covers your currency denominations. Used in closing. I dont know if you want to add a 0.5 as 50 cent piece there since those are rare.
till_type is either the 'cashier' meaning the employee id becomes the till number or 'terminal' in which the last octet of the IP address becomes the till number. If you need to customize this handling you can do so underneath the request to stop editing at a certain point.
Advanced options include
source_accno_override used to override cash account handling of various sources (such as gift certs for example)
disable_tables is no longer necessary. But you can use this if you aren't using projects and/or departments. It defaults to disabling everything.
If the directnet approach for printing does not work for you you can comment out the printer definition at the bottom of the pos.conf.pl and set up cups to process and send the file to the workstation to be printed. This adds a few seconds often, however, so where directnet works, it is preferred especially in time-critical point of sale environments.
Q : Brian Wolf
A: Chris Travers