AMX ICSP
ICSP is AMX / HARMAN's proprietary Internet Control System Protocol: a native AMX control-plane protocol for controller-to-device and controller-to-controller messaging. It is not media transport, not AV-over-IP video/audio, and not a vendor-neutral API. The firewall conversation is narrow for IP deployments: plain ICSP is normally on 1319, Secure ICSP / ICSPS is normally on 1320, and legacy NetLinx/NX UDP connection modes still matter in brownfield estates. Current MUSE documentation makes the modern split clear: URL mode is a device-initiated TCP connection to the controller on 1319 or 1320; Listen mode reverses initiation and has the device listen on 1319; NDP is a binding/discovery workflow that becomes a URL-mode-style device once created. Current HARMAN fixed-port guidance explicitly says the plain and secure ICSP listener ports are fixed on NX-based integrated controllers.
Scope: AMX ICSP — select the deployed product/version; optional services require separate selection.
protocol · Catalog reviewed 2026-09-27
By Harman/AMX
Infrastructure Requirements
- AMX / HARMAN controller or integrated NetLinx/MUSE control host
- IP reachability between controller and native ICSP endpoints where ICSP is carried over Ethernet
- device-number/system-number discipline
- explicit choice of connection mode (URL, NDP, Listen, or legacy Auto where applicable)
- secure-certificate planning if using Secure ICSP / ICSPS
- deliberate boundary planning if ICSP is relayed across controller-to-controller, ICSLan, older ICSNet, or serial-PPP paths
Network & Physical Requirements
| Port / allocation | Transport | Connection / signal flow | Feature and requirement | Evidence |
|---|---|---|---|---|
| 1319 (default) | TCP | Configured client → Configured ICSP listener | Profile requirement · Core ICSP connection AMX ICSP URL/listen mode | Source checked 2026-09-27 AMX device port inventory |
| 1320 (default) | TCP | Configured client → Secure ICSP listener | Optional · Secure ICSP Secure ICSP connection AMX secure ICSP-supported products | Source checked 2026-09-27 AMX device port inventory |
| 1319 (default) | UDP Multicast: Subnet broadcast | NetLinx controller → Local AMX devices | Profile requirement · Controller beacon Controller beacon (ICSP Blink) AMX AV/IT Administrators Guide Rev. 2.0 (2014), NetLinx/ICSLan binding profiles Legacy guide: ICSP Blink is not disableable for this documented controller profile. Check newer controller firmware separately. | Source checked 2026-09-27 Control over IP > Communication Protocols and Network Impact; Appendix ARev. 2.0, 2014-09-04 |
| 1319 (default) | UDP Multicast: 239.255.250.251 | NetLinx controller → NDP devices | Optional · NDP binding NDP binding advertisement AMX AV/IT Administrators Guide Rev. 2.0 (2014), NetLinx/ICSLan binding profiles Legacy guide: ICSP Blink is not disableable for this documented controller profile. Check newer controller firmware separately. | Source checked 2026-09-27 Control over IP > Communication Protocols and Network Impact; Appendix ARev. 2.0, 2014-09-04 |
| 1319 (default) | UDP | AMX device / controller → AMX controller / device | Optional · UDP binding UDP-bound ICSP control and keepalive AMX AV/IT Administrators Guide Rev. 2.0 (2014), NetLinx/ICSLan binding profiles Legacy guide: ICSP Blink is not disableable for this documented controller profile. Check newer controller firmware separately. | Source checked 2026-09-27 Control over IP > Communication Protocols and Network Impact; Appendix ARev. 2.0, 2014-09-04 |
Gotchas & IT Notes
- ⚠URL mode and listen mode reverse the initiator/listener placement. Set the actual endpoint roles in the project.
- ⚠Legacy UDP behavior requires its product/controller documentation; an IANA registration alone does not establish a requirement.