The Citizen CT-S651 is an 80mm direct-thermal POS receipt printer built for front-exit installation under a counter. The original CT-S651 has been discontinued and replaced by the CT-S651II, which prints faster (220mm/sec vs. 200mm/sec), keeps the same 203 dpi resolution, and adds Bluetooth and Wi-Fi interface options. Both use ESC/POS emulation, making them compatible with most major POS software.
What Is the Citizen CT-S651?
The CT-S651 is a direct thermal point-of-sale printer designed for retail counters, restaurants, and hospitality checkout stations. Its defining design choice is a front paper exit; the receipt comes out the front rather than the top, which lets you mount the printer under a counter and keep your workstation looking clean.
It prints on thermal paper (no ink or ribbon needed), supports barcode printing for coupons and loyalty codes, and includes an auto-cutter that trims each receipt automatically.
CT-S651 vs. CT-S651II What’s Actually Different?
This is the question most buyers should be asking, and it’s the one most product pages bury. The original CT-S651 has reached end-of-life and has been formally replaced by the CT-S651II, according to POSGuys’ own discontinued-product listing. If a retailer is still showing “CT-S651” in a URL or title, check the actual spec sheet many are already selling the II model under the old name.
Here’s how the two compare on the specs that matter:
| Spec | CT-S651 (original) | CT-S651II (current) |
| Print speed | 200 mm/sec (7.8 in/sec) | 220 mm/sec |
| Resolution | 203 x 203 dpi | 203 dpi |
| Interfaces | Serial, Parallel, USB, USB w/ hub, Ethernet, Powered USB | Adds Bluetooth (Apple MFi-compatible) and Wi-Fi (Premium/Compact wireless LAN) |
| Mac compatibility | Not supported | Mac OS X supported |
| Cutter lifespan | ~2.3 million cuts | 2 million cuts (rated with 200M-pulse printhead life) |
| Availability | Discontinued | Currently sold |
| Warranty | 3 years | 3 years |
Bottom line: if you’re comparing quotes and one vendor’s price looks unusually low, confirm which model you’re actually getting a discontinued unit may come with limited support and no future firmware or driver updates
Full Specifications
Based on Citizen Systems’ official datasheet for the current CT-S651II:
- Printing technology: Direct thermal
- Resolution: 203 dpi
- Max print speed: 220 mm/sec
- Max print width: 80 mm
- Paper width range: 58 / 60 / 80 / 82.5 mm
- Paper thickness: 65–85 μm
- Barcodes supported: UPC-A, UPC-E, EAN-13/8, Code 39, Code 93, Code 128, Codabar, PDF417, QR Code
- Emulation: ESC/POS
- Dimensions: 145 x 192 x 148 mm, approx. 2 kg (DC version: 145 x 192 x 120 mm, 1.6 kg)
- Cash drawer kick-out: 2 drawers
- Power: 110–240V, 50/60Hz (integrated power supply)
- Reliability: Rated for 200 million pulses or 150 km of printhead life, 2 million cuts
- Operating environment: +5°C to +45°C, 10–90% RH non-condensing
- Certifications: CE, TUV, UL, C-UL, FCC Class A, VCCI
Two facts worth flagging for buyers: the printer has no built-in main interface you choose an optional interface card (USB, Ethernet, Serial, Parallel, Bluetooth, or Wi-Fi) at purchase and it stores logos and header/footer images in onboard memory, useful for branded receipts.
Which POS Systems and Software Work With It?
The CT-S651/CT-S651II runs on ESC/POS emulation, the industry-standard command language most POS software already speaks. In practice, that means it works with:
- OPOS and JavaPOS drivers, used by many enterprise retail and restaurant platforms
- Windows 7, 10, 11, and Windows Server 2022
- Mac OS X (CT-S651II only the original CT-S651 lacked Mac support)
- Linux, via CUPS
- iOS and Android, including mobile POS setups
Because ESC/POS is so widely adopted, the printer typically integrates with cloud POS systems built on standard receipt-printer drivers rather than proprietary hardware. Before you buy, confirm with your specific POS vendor (whether that’s a cloud platform or an in-house system) that they list ESC/POS or OPOS driver support that’s the compatibility signal to look for.
Choosing the Right Interface USB, Ethernet, Serial, or Bluetooth?
Since the interface is a separate card you select at purchase, pick based on how your station is wired:
| Interface | Best for |
| USB | Single-register setups plugged directly into a POS terminal |
| Ethernet | Multi-register environments where the printer sits on the network and can be shared |
| Serial (RS-232C) | Legacy POS systems that still expect a serial connection |
| Parallel (IEEE 1284) | Older systems requiring parallel printer support |
| Bluetooth (CT-S651II only) | Tablet-based or mobile POS setups, iOS and Android compatible |
| Wi-Fi (CT-S651II only) | Wireless stations where running a network cable isn’t practical |
If you’re not sure, Ethernet is the safest default for a fixed retail or restaurant counter it’s easy to share across multiple terminals and doesn’t tie the printer to one specific machine.
Is It Still Available to Buy?
The original CT-S651 is discontinued at official channels; POSGuys’ listing directs buyers straight to the CT-S651II replacement. You may still find new-old-stock or used original CT-S651 units through marketplaces like eBay, but treat these as a budget option with no manufacturer support path going forward, not a like-for-like substitute for the current model.
A practical buying checklist before you order:
- Confirm the exact SKU (part numbers like CT-S651IIS3ETUWHP tell you interface + color)
- Check whether the interface card is included or sold separately
- Verify Mac compatibility if you’re on Apple hardware only the II supports it
- Ask the seller directly whether the unit is the original or Type II
- Confirm warranty status; used/NOS units may have expired or partial coverage
This checklist reflects common gaps we found across current listings if your team has hands-on setup notes or a specific POS integration story, that’s worth adding here for a stronger first-hand account.
Setting Up the CT-S651 Quick Driver Install Steps
- Unbox and connect power — attach the AC adapter and power cord, then power on the unit.
- Load the paper roll — open the top cover, drop in thermal paper (matching your chosen width: 58, 60, 80, or 82.5mm), and close until it clicks.
- Connect your chosen interface cable — USB, Ethernet, Serial, or pair via Bluetooth depending on your card.
- Install drivers — Citizen provides free drivers for Windows, Mac OS X, and Linux CUPS from their support site; download the one matching your OS.
- Set as default printer in your POS software’s printer settings, and run a test receipt to confirm alignment and cut function.
- Load logos/header-footer images (optional) using Citizen’s utility software if you want branded receipts.
Is the CT-S651 Right for Your Business? Restaurant vs. Retail Use
Citizen positions this printer for hospitality, kitchen, kiosk, and retail applications, and the spec sheet backs that up:
- Restaurants and bars: Front-exit design keeps the printer protected from splashes at a bar or kitchen pass — a genuine advantage over top-exit models in wet environments.
- Retail counters: Barcode printing on receipt footers supports coupon and loyalty-code use cases without extra hardware.
- Kiosks: Compact footprint and integrated power supply reduce the cabling and space needed inside a kiosk enclosure.
It’s less suited to environments needing color printing (this is direct thermal, single-color output unless you use special two-color thermal paper) or extremely high-volume 24/7 printing beyond its rated cut/print-head lifespan.
CT-S651 vs. Similar Printers
| Printer | Print Speed | Interfaces | Standout Feature |
| Citizen CT-S651II | 220 mm/sec | USB, Ethernet, Serial, Parallel, Bluetooth, Wi-Fi | Front exit, splash protection |
| Citizen CT-S601II | 220 mm/sec | Same interface family as CT-S651II | Shares core spec sheet, different chassis |
| Epson TM-T88 series | Varies by generation | USB, Ethernet, Serial, Bluetooth | Widely used industry benchmark, broad POS-software certification |
If you’re already standardized on Epson-certified POS software, check driver compatibility carefully before switching brands. ESC/POS covers most commands, but certified integrations sometimes favor one manufacturer.
Conclusion
The Citizen CT-S651 name now almost always means one of two things: a discontinued original unit, or the current CT-S651II sold under the legacy name. For a new purchase, confirm you’re getting the II model, check that your POS software supports ESC/POS or OPOS drivers, and choose the interface (USB, Ethernet, Serial, Bluetooth, or Wi-Fi) that matches how your counter is set up. Front-exit design, barcode printing, and a 3-year warranty make it a solid, no-frills choice for retail, restaurant, and kiosk checkout stations.
FAQs
Is the Citizen CT-S651 the same as the CT-S651II?
No. The original CT-S651 is discontinued and lacks Mac support and wireless interfaces. The CT-S651II is the current model, with faster print speed and added Bluetooth/Wi-Fi options.
What paper size does the CT-S651 use?
It accepts thermal paper in 58, 60, 80, or 82.5 mm widths, with a maximum print width of 80 mm.
Does the CT-S651 work with Mac?
Only the CT-S651II supports Mac OS X. The original CT-S651 does not.
What POS software works with the Citizen CT-S651?
Any software supporting ESC/POS, OPOS, or JavaPOS drivers which covers most major POS platforms should work, but confirm with your specific vendor.
How long does the printhead last?
Citizen rates the CT-S651II printhead for approximately 200 million pulses or 150 km of paper, with the cutter rated for around 2 million cuts.
Can I still buy a new original CT-S651?
Not through official Citizen channels it’s discontinued. You may find used or new-old-stock units on secondary marketplaces, but without ongoing manufacturer support.
