I started off the implementation of Bluetooth printer support by using the same concurrency model used by our WiFi printer code and running Bluetooth printing and printer discovery blocks on a global concurrent queue. I quickly found what appeared to be a non-deterministic bug — sometimes I could print a receipt with no problem, and other times it would fail part way through. What I was in fact encountering was a timer firing and searching for connected printers while the app was in the middle of sending data to a printer. While this behavior was perfectly acceptable in communication for WiFi printers (TCP supports multiple simultaneous connections), it totally broke down in the new communication channel. It became clear that some kind of mutual exclusion was necessary to prevent this kind of collision.
This is an impact printer. So it makes a noise when it prints. Why would you want this? You might want it if you are in an area such as a kitchen where thermal paper receipts don’t print as well because of moisture in the area. You would not want this noise around customers. But if you have a moist area such as a busy kitchen this impact printer may be what you can use. Here is the user manual for the Star Micronics SP742ML.
Drawer made from robust Steel. 1 x Cash drawer with RJ11 cable. Thermal Receipt Printer. THERMAL RECEIPT PRINTER. 1 Fixed mount(1 Saddle stande with one turning axis, 1 Link pole with one Nut Sheath, …
Another nice touch is that they include a CD which allows you to customize the printer (add logos, sync with POS systems, custom data to add once the receipt is printed, etc). Keep in mind though, this customization works with certain POS systems, not all. On Square, I can’t tell the printer to print out all of the extra stuff since the POS for Square is very simplified.
Complete your countertop POS system with this Square register kit. Print paper receipts, daily sales reports and summaries right from your iPad. Includes, Square reader, Star Ethernet Printer, APG 13″ Vasario Cash Drawer, drawer cable, extra 2 rolls of thermal receipt paper and installation support. 
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Bluetooth desktop receipt printer. Star printer, TSP654IIBi2-24, is the Bluetooth printer model which is one model in the TSP650 series of printers. TSP650 (654II), thermal, auto-cutter, Bluetooth iOS…
When you connect to the USB Receipt Printer or Ethernet Receipt Printer with the included cable, the cash drawer will open every time you complete a cash sale. Or use the included keys to manually open.
Square Register Socket 7CI Bluetooth Cordless Hand Scanner (CHS), Socket Mobile CHS 7CI Cordless Barcode Scanner, 1D Imager, Includes Socket CHS 7CI Barcode Scanner, Two AAA NiMH Rechargeable Batteries, USB AC Charging Kit, Lanyard/Belt Clip with Retractable Tether, Dark Gray Color – CX2870-1409
POSMicro – Using a Mobile Printer with Square
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Star TSP650II TSP654IIBTI Printer (Bluetooth Interface / Auto Cutter / Dark Gray). Sorry No Drivers cd included. drivers can be downloaded from Star Micronics website. Setup is pretty simple. Press an…
Features: 100% Brand new and high quality! Compared to conventional thermal receipt printer, the printer has a smaller mini body, more reliable capability, more stable printing and portable advantages…
The STAR MICRONICS SM-T300I is also a light weight receipt printer. But it’s very durable and rugged. It’s also Apple MFi certified for iOS phone and iPads. It also works with Android and Windows. It’s been tested to take a little bit of beating and is used by people who are outside a lot. Having said that the price is higher than other printers. If you need something rugged, this device may be the one for you. But if you don’t. You will want to look at something else as this device can get expensive. The SM-T300i is easy to use. There is a well written and very detailed user manual. The user manual gives details on how to configure the receipt printer and how to load paper. Here is a link to the Star Micronics SM-T300i User Manual.
EOM-POS Heavy Duty Cash Register Money Drawer + Mounting Brackets for Under Counter Installation. Compatible with Square Stand [Receipt Printer Required]. Built in cable to connect to receipt printer.
* All credit sale plans are issued by Square, Inc. Plans are not available to merchants located in AL, DE, MS, MO, NH, and TN. The individual authorized to act on behalf of the business must be a U.S. citizen or permanent resident and at least 18 years old. Valid U.S. bank account and Social Security number or Individual Taxpayer Identification Number are required. Plans may be selected from 3-, 6-, 12-, or 24-month terms and are based on the financing amount requested. The finance charge amount and installment payment amounts will depend on the repayment term selected. Sales tax, where applicable, cannot be financed and will be due upon acceptance of contract. The final payment will be equal to or less than the regular monthly payment. All plans are subject to approval based on credit and other factors.
NOT FOR USE WITH SQUARE STAND! If using a Square Stand consider the Square Stand Starter kit which has a printer that plugs into the stand. The printer in this kit must be plugged into your router.    
The Star Micronics SM-S230i is light weight at only 7.7 ounces. It is small and easy to carry around. If you’re someone who sell at a farmers market, craft fair or some other place where mobility is very important, the Star Micronics SM-S230i may be what you need. It uses thermal paper and connects to your iPhone, iPad with bluetooth or USB. ​Here is the user manual for the Star Micronics SM-S230i.
** If you are using the Square Register app, this is the USB version of the Star TSP143 Printer and must be used with the Square Stand Hardware. You will need a Star ethernet or bluetooth printer if you are using Square or a similar Point of Sale app with the tablet or device by itself.
EASY INTEGRATION – Star Micronics Printer and Cash Drawer Easily integrate with Square POS system. STAR MICRONICS RECEIPT PRINTER – Integrates easily with Square POS. Comparable to APG 16 x 16 Vasario…
Just click the Transaction and the Receipt will preview on the right-hand side. At the bottom, you’ll see the receipt number (ex: Receipt #H8R5). Click that and it will show you the digital version of the receipt. From there you’re good to print on the standard 8×11 printer paper.
If you want a small and easy to carry receipt printer, this may be it. It weighs less than half a pound. It is easy to carry around. For people who sell at craft shows, farmers markets and historical fairs this may be the receipt printer.
I spent years in jobs that included lots of cash handling. This cash drawer is the nicest I’ve seen. It’s solid build will last for years and its finish is just lovely. It triggers cleanly and the drawer all but shoots out when triggered. I’m very pleased.
It is a simple process all I can think is that square gets a percentage of royalties from their supported printer sales and thats why they are locking everything down to these ridiculously overpriced pieces of equipment. 
Implementing Bluetooth printing introduced new limitations in parallel processing and communication that required me to rethink how we manage concurrency in our printing system. If you’re familiar with multi-threaded code, you probably already realize that expensive operations, such as peripheral communication, downloading and uploading, and heavy computation, are best run asynchronously off the main UI thread. In our code for WiFi printing, this is done using the most basic functionality of Grand Central Dispatch (GCD), one of Apple’s built-in mechanisms for managing concurrent tasks. For more detailed info about GCD, read Apple’s documentation . Each print operation and printer discovery operation is added to a global concurrent queue that runs the code on a private thread, abstracting away the mechanics of threading. The result of this is that the different operations are allowed to run in parallel with no restraints and no control.
An update 11/21/15 Had it working fine with Amazon local register until Amazon shut it down, so bought the PayPal chip and card reader- the updated paypal iOs app will not print to this printer. (iOs 9.1/ iPad 3). The workaround I found was to turn this printer in to an airprint printer- it’s a bit of a hack, instructions are out there, problem being you must have a host computer on the network. To be clear- this is a PayPal issue- not a fault of the printer.
If you accept credit card payments from your customers at your place of business, you’ll want a receipt printer. A receipt printer automatically prints a receipt for your customer when they make a purchase.
You can add your logo and text to your receipt. This is done with software that is included with the receipt printer. By adding your logo to your receipts you have a place to advertise your business. You can also put your phone number on your receipt or your website URL. This is a good thing to do if you’re selling at a craft show, fair, farmers market and etc. The customer may not remember your name and may not go online to search for your website. But if you put your website on the receipt you have a better chance of the customers visiting your website to make a purchase.
My first inclination, having just taken a class in C++ using pthreads, was to simply use locks. I created a shared NSLock through a class method and locked before listening and printing, as described in Apple’s Threading Programming Guide. I was excited when it accomplished the mutual exclusion I wanted, but my coworkers were less thrilled about using such a low-level solution given the higher level abstractions available in iOS. In search of a higher-level solution, I replaced the global concurrent queue on which I was running the printer code with a serial dispatch queue, allowing only one block to be run at once. I was getting warmer, but my new solution still raised some concerns.
iPad-based POS (Point of Sale) systems have become increasingly popular. In addition to saving money on upfront costs, these systems have streamlined operations in the modern merchant and Square Register is quickly becoming one of the most convenient and coolest ways for small businesses to process transactions. Tablet and smartphone based systems are also being increasingly used for inventory control – from the retail floor to the warehouse – and by sales personnel assisting customers in-store and on the convention floor. The hardware options for Square Stand differ from those below. For Square Stand hardware options, or to learn how to set up hardware with Square Stand, click here: here.
Print 58mm wide thermal paper, with 100km reliability TPH life. Paper Width: 58mm( -0.1mm). POS-5805DD mini thermal printer is compatible for iOS Android Windows devices, supporting BT(wireless), USB …
Great product and great company to work with. I at first ordered the TSP143U which is a USB Printer to work with a Tablet to set up a POS system at my business. Once I got it, I realized that if I had the printer plugged into the tablet there was no additional port to then charge the tablet. I contacted the company and they gladly accepted my return and let me reorder this LAN Printer. I highly recommend this vendor and their product.
Square systems are primarily compatible with Ethernet or Bluetooth interface printers (depending on the tablet you are using, Android tablets with USB ports and USB On-The-Go or USB Host mode can use USB interface printers). The compatible printers for Square systems are as follows:
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Edit to say that the network issues I mentioned were tied to the wireless router we were using. Replaced that piece and the printer started working great. I still recommend purchasing as a package for better price and customer service, but not a bad piece of equipment.