IS215ISBBH3A Bypass Splitter Communication Switch

The IS215ISBBH3A is the H3A build of General Electric's Speedtronic Mark VI ISBB — the splitter, or bypass, communication switch used to distribute network traffic in a Mark VI turbine control system. Like the rest of the ISBB line, it is a compact, self-contained, ventilated module that installs inline on the Mark VI Ethernet I/O network rather than plugging into the VME rack. It takes a communication drop and splits it, so a single full-duplex Ethernet link can be routed out to the transmit and receive paths that feed the rest of the system.

Function within the Mark VI Ethernet I/O network

Mark VI I/O data travels on an Ethernet network (IONet) that connects the UCVx and UCCx controllers, their VCMI communication interfaces, and the distributed I/O packs. The ISBB's role is passive distribution: it moves the signal along and splits it, and on documented ISBB units a Receiver Active LED reports whether the upstream drop is transmitting on a good cable. Note that GE built the ISBB in more than one hardware version; the well-documented port arrangement (Full Duplex P1, Transmit Out P2, Receive In P3) belongs to the H2A build, so treat the H3A as its own variant and confirm the physical interface against your unit rather than assuming an exact match.

Rule Out the Usual Suspects First

A communication dropout on a Mark VI is rarely the splitter's own doing. Before ordering an IS215ISBBH3A, work the honest checklist:

• Believe the Receiver Active LED. When it is off, the documented meaning is an upstream cable fault or a source that has stopped transmitting — look there before condemning the box.
• Cabling before electronics. Reseat and inspect the Ethernet drops and connectors; a marginal lead is the most common cause of these symptoms.
• Check the source. A stalled controller, quiet VCMI or failed upstream power supply produces exactly the silence a healthy splitter would report.
• Hardware vs. configuration. IONet address conflicts, firmware/ToolboxST mismatches and I/O pack faults masquerade as lost communication.
• Reference a matching drop. Compare behavior against an identical splitter elsewhere on the machine to localize the fault.

If the source and cabling check out and a comparable unit works in its place, then the IS215ISBBH3A is the right thing to replace.

What the H3A suffix tells you

Read the number in segments: IS215 is the Mark VI assembly family and GE lineage, ISBB is the splitter/communication-switch function, and H3A is the specific hardware version and revision. The H-number is the differentiator you must match — H1A, H2A and H3A are distinct builds and are not automatically interchangeable. Send us a label photo if you are unsure, and see the GE Speedtronic Part Number Decoder for the full breakdown.

Boards it works alongside

In the same communication path you will find the VCMI interface, the UCVx/UCCx main controllers and the Mark VI I/O packs. Our GE Mark VI IS200 Boards collection covers those companions, and the GE Speedtronic Turbine Control Boards catalog spans the wider system if you are sourcing several parts at once.

Speeding up your RFQ

• Full part number and suffix as printed (IS215ISBBH3A), plus any extended catalog number.
• A photo of the module label and its port markings.
• Turbine model, Mark VI generation, and simplex or TMR (<R>/<S>/<T>) configuration.
• Quantity, required lead time, and ControlST/ToolboxST version if known.

Request a Quote for the H3A

This IS215ISBBH3A is offered clean and tested with a one-year warranty. Share your requirement and we will return a quote within 24 hours. We ship worldwide DDP, welcome purchase orders from qualified buyers, and can propose a verified alternate if your exact build is hard to find. Click Request a Quote to get moving.

General Information about the Product
Part Number	IS215ISBBH3A Mark VI IS215
Description	IS215ISBBH3A By General Electric IBB Bypass Splitter Communication Switch
Condition	used Clean and Tested With 1 Year Warranty.