A4H124-24FX In Stock | Enterasys C2R124-24FX Compatible

Description

Product Introduction

The Enterasys A4H124-24FX is a 24-port Fast Ethernet fiber switch from the C2 series. If you’re dealing with a plant floor network running back to the 1990s or early 2000s, you’ve seen these gray boxes in the bottom of racks—they were the go-to for connecting remote I/O or SCADA nodes over fiber to avoid ground loops and EMI.

It’s all 100BASE-FX on MT-RJ connectors. No copper. No gigabit. But it’s reliable. We’ve pulled these out of paper mills after 15 years with the fans still spinning. The trade-off? It’s loud, runs hot, and lacks modern security features.

Key Technical Specifications

Compatible Replacement Models

The A4H124-24FX is a legacy part. If you’re keeping an old line running, you need exact matches. If you’re modernizing, here’s the path:

• ✅ Drop-in Replacement: Enterasys C2R124-24FX. Same hardware. Same MAC addresses. The “C2R” was Enterasys’ later part number for the identical unit. Also, Extreme Networks C2R124-24FX (post-acquisition branding) is the same switch. If you have a dead one, any of these will swap without config changes.
• ⚠️ Software Compatible: Extreme Networks Summit X440-G2-24t-10G. This is a modern equivalent but with copper ports. You’d need fiber-to-copper media converters (SFP based) and you’re rewriting the config from scratch—CLI is different. Budget 4-8 hours for cutover.
• ❌ Hardware Incompatible: Enterasys C2G124-24 (Copper version). Do not try to plug your MT-RJ fiber patch cables into an RJ45 port. Sounds obvious, but we’ve seen field techs order the wrong SKU and show up with a box of copper switches for a fiber run. Verify connector type before ordering.

Frequently Asked Questions (FAQ)

Q: What kind of fiber cable works with the MT-RJ ports?
You need duplex multimode fiber with MT-RJ connectors. These are the small square connectors—not the round LC or SC types. Typical spec is 62.5/125µm (OM1) or 50/125µm (OM2) multimode. Single-mode won’t work unless you’re running extremely short distances with mode conditioning cables, which we don’t recommend.

Q: Why are the fans so loud on this switch?
Because they’re 40mm high-speed fans designed to move air through a 1U chassis packed with 24 fiber transceivers. Those transceivers run hot—they’re essentially lasers. If the fans quiet down or stop, the switch will overheat and start dropping packets. Replace fans proactively every 5 years.

Q: Can I manage this switch through a web browser?
Yes, but it’s old. The web interface is Java-based. Modern browsers block Java by default. You’ll likely need to enable it in Internet Explorer compatibility mode or fall back to the serial console or Telnet/SSH (if SSH is enabled—many older units only run Telnet). We always keep a console cable handy for these.

Q: What’s the distance limitation on the 100FX ports?
Multimode fiber with 100BASE-FX is good for 2 kilometers (approx. 6,500 feet) at full duplex. Half-duplex cuts that to 412 meters due to CSMA/CD timing. On a plant floor, that’s rarely an issue—you’re usually running between buildings or across a large site.

Q: My A4H124-24FX is showing “Link” but no traffic. What’s wrong?
Check the duplex settings. 100FX requires both ends to match. If one side is hard-set to full duplex and the other is auto-negotiating, you’ll get link but massive packet loss. On this switch, we recommend hard-setting both ends to 100FDx (Full Duplex) rather than trusting auto-neg on old fiber gear.

Q: Is Enterasys still in business?
No. Enterasys was acquired by Extreme Networks in 2013. The C2 series is long discontinued. Extreme no longer manufactures these, but they do provide legacy support documentation. For hardware, you’re in the secondary market. Buy from a supplier who tests and cleans them—dust in the MT-RJ receptacles is a common cause of intermittent link.

Q: What’s the power consumption?
About 85 watts typical, 120 watts with both power supplies installed and running. Use a dedicated 15A circuit if you’re stacking multiple units. These old switches don’t play nice with under-sized UPS units—they have high inrush current on startup.

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