The GST P-9940A Class A RS485 Network Card (ERP code KTI07001001P994, HSN code 85311020) is an internal communication expansion module manufactured by Gulf Security Technology Co., Ltd. It enables peer-to-peer Class A networking across GST addressable fire alarm control systems and remote repeater hardware.
Compatible Fire Alarm Control Panels and Repeaters
The P-9940A module is engineered specifically for direct installation within the following Gulf Security Technology addressable life safety platforms:
- GST200 Series Addressable Panels: Fully compatible with the GST200 single-loop panel, the GST200-2 two-loop panel, and the GST200N addressable fire alarm control panel.
- Network Repeater Units: Compatible with the GST-NRP00 network repeater panel, allowing repeater stations to integrate into the primary RS-485 Class A loop.
- Network Scale: Supports multi-panel networks consisting of up to 32 GST series control panels communicating in a shared peer-to-peer architecture.
Main Board Hardware Interfacing
The P-9940A is designed as an internal printed circuit board assembly that secures directly inside the fire alarm control panel cabinet using screw fixings. Connection between the card and the panel main board is established via a dedicated multi-pin ribbon assembly:
- Card Interface Port: Designated as port XS1 on the P-9940A circuit board.
- Panel Main Board Port: Connects to terminal socket XS12 on GST 200 series main boards.
- Interconnect Cable: Uses the dedicated Flat Cable HF-20 ribbon cable assembly.
- Handling Requirement: The network card must never be inserted, connected, or removed while the host control panel is energized. The panel must be completely powered down prior to card installation or maintenance.
Network Loop Topology and Transmission Parameters
The P-9940A card provides two photoelectrically isolated RS-485 communication interfaces: Master Interface (terminals A1, B1) and Slave Interface (terminals A2, B2). These dual isolated interfaces are configured in a closed Class A ring network:
- Loop Wiring Scheme: Terminal set A1B1 on one panel connects directly to terminal set A2B2 of the neighboring control panel (maintaining polarity alignment of A1 to A2 and B1 to B2) until the loop closes back to the originating panel.
- Redundant Routing: The peer-to-peer ring topology provides communication path redundancy, ensuring network data continues to transmit across the remaining segments if a cable break occurs.
- Transmission Baud Rate: Operates at a fixed communication speed of 2400 bps.
- Inter-Node Cabling Distance: The maximum allowable transmission distance between two adjacent network nodes is 1200 meters.
- Conductor Specification: Requires fire alarm field cabling with a cross-sectional conductor area of 1.0 mm² or greater twisted pair; shielded twisted pair is recommended for all inter-panel loop runs.
Panel Registration and Diagnostic Indication
System integration requires software registration on the host control panel. Upon entering panel calibration mode, pressing key SK1 resets the main board; the panel screen displays Color CRT OK to verify that the P-9940A network card has been successfully recognized and registered. Status monitoring is verified on the card via three dedicated diagnostic LEDs:
- HL1 (Red): Main board communication indicator. Flashes steadily when data communication with the host panel main board is operating normally.
- HL2 (Green): Master Interface (A1B1) communication indicator. Illuminates continuously when the primary RS-485 channel is functional and idle.
- HL3 (Green): Slave Interface (A2B2) communication indicator. Illuminates continuously when the secondary RS-485 channel is functional and idle.
