The Simplex 4100-1249 is a 100 W Class A audio adapter for 4100ES voice systems. First, the module converts the six on-board NACs on a 100 W amplifier to Class A operation. Then, each NAC routes through both A and B terminals so that field power continues under a single fault. As a result, the speaker circuit survives a short or open on the run.
Simplex 4100-1249 Capacity and Limits
Each converted NAC accepts up to 2 A, 50 W, or 100 speakers — whichever limit hits first. Specifically, the 2 A / 50 W rating applies per NAC, not per amplifier. In addition, the adapter mounts on the 100 W amplifier assembly itself. Furthermore, the assembly serves 4100U and 4100ES voice systems.
How Class A Survivability Works
In Class B wiring, a single open between the panel and the speakers silences everything downstream of the break. However, Class A wiring loops back to the panel. As a result, the adapter feeds power from both ends of the loop. Therefore, a single open or short on the field wiring still keeps every speaker driven.
Installation Reference
Refer to the Simplex Class A and Expansion NAC Modules Installation Instructions for module seating and field wiring detail.
For more information, contact the Life Safety Consultants team at (888) 557-0558, or email us at: sales@lifesafetycom.com
Additional information
| Weight | 1 lbs |
|---|---|
| Dimensions | 13.1 × 10.3 × 2.8 in |
| Condition | New |
| Manufacturers | Simplex |
| Part Type | Replacement Part |







