Allen-Bradley 1756-CN2 ControlLogix ControlNet – Repair Available

Allen-Bradley 1756-CN2 ControlLogix ControlNet bridge (2nd generation), ControlNet bridge module, standard media, 5 Mbps, second generation with 128 connections. NJT Automation offers mail-in repair for the 1756-CN2 with a 1-year warranty; replacement pricing is available on request.

Mail-in repair available now. Returned with a 1-year warranty. Replacement pricing on request.

Allen-Bradley 1756-CN2 ControlLogix ControlNet bridge (2nd generation) – front view

Request Replacement Quote Request Repair QuoteEstimated $1,440.00

Part Number	1756-CN2
Price	On Request Previously sold for $599.99 USDAvailability and condition determine final quote.
Description	ControlLogix ControlNet bridge (2nd generation).
Shipping	UPS Ground included \| Next-Day Air and Worldwide Shipping available at checkout
Warranty	1-year full-function warranty provided by NJT Automation. Warranty details Included 1 year, full-function 2 years +15% of product price ($90.00) 3 years +25% of product price ($150.00) View full warranty policy
Returns	90-day free returns. View return policy
Exchange	Send us your defective 1756-CN2 after your purchase for a 10% core credit. We also purchase old or damaged parts outright.

Availability

Available Level 1

This part is available through our Level 1 supplier network. Request a quote to confirm quantity, price, and next-day shipping options.

Inventory Level 1 RFQ

Level 1 parts come from vetted US suppliers we have worked with for years. Each unit is checked before it ships, so counterfeits, repackaged items sold as new, and worn-out equipment do not reach you. Every part carries the same NJT warranty and return policy as our own stock.

Request Quote Learn more about Inventory Levels

Repairs

1756-CN2 Mail-In Repair Service

Estimated: $1,440.00

How the Process Works:

Submit Your RFQ: Complete the request-for-quote (RFQ) form with your exact requirements.
Receive a Quote: We respond ASAP - within 1 hour during business hours.
Approve and Pay: Agree to the quoted price, and we will issue an invoice payable via credit card or your preferred method.
Direct Shipping: Our normal shipping time is 3-5 business days, during which we thoroughly inspect and certify items to meet our high standards. If you request next-day air delivery, the item will be sent directly to you and arrive the following business day. Please note: These items are NOT available for local pickup at NJT Automation's location.

What We Offer

We source genuine parts from trusted U.S. channels and stand behind what we sell.

Our network has millions of parts ready to be delivered now.
Complete Transparency: Clear information on item availability.
Well-vetted components from trusted suppliers sourced from the USA.
Technical Support: Assistance, troubleshooting and hardware repairs.
Minimal Markup: The best sourcing service at a minimal cost.
Quick Delivery: Fast access to the parts you need to get your machines back up and running.
Dropship available • No branding on packaging

Part Number Decoder

ControlLogix ControlNet bridge (2nd generation)

1756CN2

ControlNet bridge module, standard media, 5 Mbps, second generation with 128 connections.

1756: BulletinControlLogix: Rockwell Automation's chassis-based control platform (controllers, I/O, communication modules, power supplies and chassis).
CN2: Module codeControlNet bridge module, standard media, 5 Mbps, second generation with 128 connections.

Decoded from the Rockwell Automation catalog-number structure. Series and firmware revision are printed on the product label, not encoded here.

Physical Data

Weight and DimensionsWeight0.62 lb (0.28 kg)H × W × D5.7 × 1.4 × 5.7 in. (145 × 35 × 145 mm)

Weight	0.28 kg (0.62 lb) Typical unit weight
Dimensions (H × W × D)	145 × 35 × 145 mm (5.7 × 1.4 × 5.7 in.) Single-slot module
Shipping Weight	0.81 kg (1.78 lb) Estimated: unit weight plus box and packing material; bills as 2 lb
Shipping Box (L × W × H)	12 × 12 × 8 in. (305 × 305 × 203 mm) Smallest standard box fitting the product with 3 in. cushioning per side

Product weight and dimensions are typical manufacturer-published values and may differ by series or option. Shipping box and weight are estimates for freight planning; the packed unit may ship in a different box.

Datasheet

Datasheet available for download

Generated from product specifications; not an official Allen-Bradley datasheet. For an official datasheet, contact Allen-Bradley or an authorized distributor.

Similar Part Numbers

1756-DHRIO Module code: Data Highway Plus / Remote I/O module
1756-HIST2G Module code: FactoryTalk Historian Machine Edition module with 2 GB
1756-OF8I Module code: 8-channel isolated analog output module
1756-RM2 Module code: Redundancy module, second generation

Allen Bradley Information

Lifecycle: Discontinued. Verify current status with the manufacturer.

Alternate Part Numbers

1756CN2

Previously sold 1756-CN2

1 sold

NJT Automation has supplied and shipped one 1756-CN2 ControlLogix ControlNet bridge in 2024; request a quote and we will source another from our supplier network.

Sold: 1 in 2024
Price: $600
Series: C × 1

The one 1756-CN2 ControlLogix ControlNet bridge sold in 2024 was unused surplus and went for $600.

Sold

Allen Bradley 1756-CN2 / 1756CN2 Ser C ControlLogix Communication Module

$599.99 USD

Unused surplus (new old stock)

Request Quote

Can the 1756-CN2 be repaired?

Yes. NJT Automation offers mail-in repair for the 1756-CN2, including diagnostic evaluation, component-level repair, and functional testing.

NJT Managed Repair

One vendor. One warranty. NJT manages the entire process.

1-year full-function NJT warranty, with 2- and 3-year options available
Rush service available for production-critical repairs
No evaluation or diagnostic charges
No repair, no charge
"Unrepairable" is not an option
Pre-paid UPS shipping label provided for sending your unit in
$650 minimum repair charge, shipping included both ways

Get an NJT Repair Quote

Looking for another option? For lower-cost repairs or if you prefer to work directly with an independent repair specialist, compare bids through RepairMode. RepairMode providers operate independently and set their own pricing and warranty terms.

Find a PLC repair specialiston RepairMode.com ↗

Common 1756-CN2 failures

Failure patterns we regularly see on ControlLogix ControlNet bridge (2nd generation) hardware like the 1756-CN2:

Channel A / B LEDs flashing red: failed transceiver or media problem on the coax segment
Node drops off the ControlNet keeper, scheduled connections fault (bad BNC tap, termination or module)
Redundant media (CNBR / CN2R) running on one channel because the other transceiver has failed
Node-address rotary switches worn or intermittent, causing a duplicate-node fault
Module fails to complete power-up self-test after backplane voltage sag

Repair or replace?

ReplaceReplacement ControlLogix ControlNet bridge (2nd generation) units are usually surplus. Swap the 1756-CN2 when the network is down and a tested unit is available. Check that the series and firmware match the rest of the network. We source the 1756-CN2 on request, so weigh that lead time against a repair turnaround.

RepairRepair is often the better value on the 1756-CN2: legacy network hardware fails at the connectors, drivers and power section rather than the logic, and a repaired unit keeps a known-good module on an aging network without a compatibility risk. Most 1756-CN2 units reach our bench with one of two symptoms: “Channel A / B LEDs flashing red” or “Node-address rotary switches worn or intermittent”. Already swapped it out? Repairing the failed 1756-CN2 turns it into a tested spare, and on an older platform that spare can be hard to buy later. Our estimated $1,440.00 repair of the 1756-CN2 includes full-function testing and a 1-year warranty.

Request a Repair Quote

Text photos of the faulty unit and the symptoms to (414) 331-5954.

Start Your Repair Today

Related services:PLC Repair All Repair Services

All product photos were taken by NJT Automation. Test videos originated from either NJT Automation internally or from repair technicians within our network.

Still have questions?

Find answers to shipping, warranties, repairs, and more.

Frequently Asked Questions

What is the 1756-CN2?

The Allen-Bradley 1756-CN2 is a ControlLogix ControlNet bridge (2nd generation): ControlNet bridge module, standard media, 5 Mbps, second generation with 128 connections.

What condition is the 1756-CN2 in?

The 1756-CN2 is available in Unused surplus / Refurbished / Used condition. We can quote this part in unused surplus, refurbished, or used condition depending on availability and your preference. Specify your requirement in the RFQ.

When does this part ship?

This 1756-CN2 is sourced on request, so sourcing and quote timelines apply. Request a quote and we'll confirm availability and lead time. Many parts can be sourced within a few business days through our Level 1 supplier network.

Can you ship this next-day air?

Yes. UPS Next Day Air is available at checkout for the 1756-CN2 ControlLogix ControlNet bridge (2nd generation). Place your order before 5:00 PM Central on a business day and your in-stock item ships the same day for next-business-day delivery.

Can I pick this item up locally?

Yes. Once your 1756-CN2 has been sourced and is ready, free local pickup is available at NJT Automation, 2122 N Prospect Ave, Milwaukee, WI, during business hours.