Our take
The Lexmark T640n is a monochrome laser printer built around a wired shared queue. Lexmark identifies part 20G0150 as the T640n, rates it up to 35 pages per minute, and recommends a 3,000–14,000 page monthly range. Standard connections include Ethernet, USB and parallel, while standard paper input is 350 sheets. The configuration distinction matters: duplex is an optional unit, and wireless needs optional hardware. Buyers comparing used machines should verify the installed options instead of assuming that the T640 family name guarantees them. Its speed and monthly band make it more appropriate for a recurring office queue than for someone seeking a compact wireless desk printer.
A wired office queue that can use the T640n's rated pace and monthly recommendation, with staff prepared to verify or add optional duplex hardware..
Choose another configuration if automatic two-sided printing or built-in Wi-Fi must be ready out of the box.
Pros & cons
What could work for you, and what to consider before buying.
What works in its favor
- Lexmark's 35-ppm rating and 3,000–14,000 recommended monthly range suit recurring workgroup documents.
- Ethernet, USB and parallel give the standard model several wired installation paths.
- The 350-sheet standard input is a documented baseline before optional trays are considered.
What to weigh up
- Automatic duplex is optional, so the exact unit needs an installed duplex component for hands-off two-sided jobs.
- Wireless also requires optional hardware; the standard T640n is not a Wi-Fi printer.
- The manufacturer's 200,000-page duty-cycle ceiling is not a recommended monthly target.
Specifications and exact model details
The key details
| Model covered | T640n |
|---|---|
| Main functions | Monochrome laser print-only; up to 35 ppm Letter |
| Print output | 350-sheet standard input; automatic duplex requires an optional unit |
| Two-sided printing | Ethernet, USB and parallel standard; 3,000–14,000 recommended pages/month |
Performance figures are manufacturer claims. Source checked October 16, 2026. Regional models and included accessories can differ.
Full review: how the features affect your choice
What the features mean for you
Use the rated speed as a queue comparison
Lexmark rates the T640n at up to 35 pages per minute on Letter paper. That is a useful specification for comparing text-heavy office jobs, but it does not promise a fixed completion time for complex pages, startup from sleep, or every driver setting. The model prints monochrome documents only, so it fits a team that can route color jobs elsewhere. Lexmark's recommended monthly volume is 3,000–14,000 pages; compare the routine workload with that range rather than using the separate duty-cycle maximum as a target. ([Lexmark T640n specifications](https://www.lexmark.com/en_us/printers/printer/2669/lexmark-t640n)).
Check the duplex option on the exact unit
The T640n does not include automatic duplex in its standard configuration; Lexmark lists a separate duplex unit as an option. A buyer who regularly prints two-sided handbooks or reports should inspect the rear paper path and verify the option is installed and working. Without it, staff must use a manual workflow or print one side at a time. An accessory listing for the broader T640 family does not prove that a used machine includes that component, so confirm the unit's part and installed equipment before counting it as automatic duplex.
Standard input totals 350 sheets
Lexmark lists a 250-sheet tray and a 100-sheet multipurpose feed as standard, for 350 sheets of baseline input. That capacity allows a team to keep a main paper supply loaded while reserving the multipurpose feed for alternate stock, but it is not evidence that optional drawers are included. Confirm which trays arrive with a particular unit and make sure their guides move freely. If a workgroup frequently switches sizes or stocks, the basic two-source arrangement may be less convenient than a printer configured with additional feeders.
Plan a wired connection
Ethernet, USB and parallel are listed as standard T640n interfaces. The wired Ethernet port suits a shared office network, and USB can serve a directly attached workstation. Wireless networking is an optional server accessory rather than a built-in radio, so a Wi-Fi-only setup should not treat the model as ready for wireless printing. Check the network port and supported driver path on a used unit, especially if it will join a managed office network. The available ports describe the printer configuration; they do not confirm a cable is included with an offer.
Use the recommended range for workload fit
Lexmark recommends 3,000–14,000 pages per month and publishes a much higher duty-cycle ceiling. These figures answer different questions: the recommendation is the practical volume range for a planned workload, while the ceiling is not an endorsement of continuous operation at that level. A routine well below the band may leave a large office machine underused; a routine above it merits a model with an appropriate recommendation. For a used T640n, separately inspect wear and maintenance history because a model rating cannot establish the condition of an individual printer.
Compare for your needs
For built-in duplex choose a T640 configuration that includes it or another printer with standard automatic duplex; for wireless-first use, choose a model with a documented built-in radio.
Find the undefined that fits you.
Tell us what matters. We’ll help you weigh the options.
Before you buy
What is the T640n's rated speed?
Lexmark lists up to 35 pages per minute on Letter paper for the T640n.
Does the T640n include automatic duplex?
No. Lexmark lists a duplex unit as optional, so verify that the exact printer has the accessory installed.
How does the standard model connect to a network?
Ethernet is standard; USB and parallel are also listed. Wireless requires optional hardware.
What monthly workload does Lexmark recommend?
Lexmark lists 3,000–14,000 pages per month as the recommended range; its higher duty-cycle ceiling is not a monthly target.
Where can I check the current price?
Use the Amazon link for current offers. Check the exact model, seller, product condition, delivery, and return terms. This page does not display a live price or confirm stock.
Sources and review basis
Sources & review basis
We use the linked product documentation for the features above. Our suitability notes and buying advice are editorial judgments based on those features, not measured performance results.
- Lexmark U.S. T640n product specifications and part mapping ↗ — checked October 16, 2026.
- Lexmark U.S. mapping of part 20G0150 to T640n, speed, standard input, interfaces, optional duplex and recommended volume ↗ — checked October 16, 2026.
The decision
The T640n suits a wired monochrome queue when its 35-ppm rating and recommended range fit the workload and optional duplex is not assumed.
Is it the right fit?
Check the exact model and today’s offers on Amazon.