GST P 9940A Class A RS485 Network Card

KTI07001001P994

Product Description

The GST P-9940A is an internal Class A RS-485 network interface card engineered to establish fault-tolerant, peer-to-peer ring communication between GST addressable fire alarm control panels.

Make / Brand: GST
Model: P-9940A
Communication Protocol: RS-485 Class A loop network
Network Topology: Peer-to-peer ring topology with cable-break redundancy
Communication Interfaces: 2 photoelectric isolation RS-485 ports (Master A1B1, Slave A2B2)
Baud Rate: 2400 bps
Maximum Distance: Up to 1200 m between adjacent nodes
Network Capacity: Supports interconnection of up to 32 GST series control panels
Diagnostic LEDs: HL1 (Red, main board link), HL2 (Green, Master A1B1 link), HL3 (Green, Slave A2B2 link)
Interconnect Cable: Flat ribbon cable HF-20 to XS12 main board terminal
Recommended Transmission Medium: 1.0 mm² or higher twisted pair (shielded twisted pair recommended)
Compatibility: GST200, GST200-2, and GST200N fire alarm control panels; GST-NRP00 repeater panel
Operating Environment: 0°C to +40°C, ≤95% RH non-condensing
Mounting: Cabinet screw-mount internal installation

KTI07001001P994

Price

₹ 13,943.40 excl. GST

+ 18.00% GST. Freight after pincode at cart.

Registered dealers see net rates after login

Product Details
Available Brands	GST
Unit	Numbers
HSN Code	85311020
Weight	0.1 kg
Warranty	12 Months Warranty
Tags/categories	Safety Fire Safety Solutions Fire Alarm System Addressable Fire Alarm System

Usually dispatched within 6 days

About this product .

The GST P-9940A Class A RS485 Network Card is a dedicated internal networking module designed to provide secure, redundant data transmission across distributed fire alarm systems. Built as a rigid printed circuit board assembly, the card secures directly into the panel chassis using mechanical fasteners and interfaces with the motherboard via an HF-20 multi-conductor flat ribbon cable.
Equipped with dual photoelectrically isolated RS-485 transceivers, the module separates field wiring electrical transients and common-mode noise from sensitive host control electronics. It provides designated master terminals (A1B1) and slave terminals (A2B2) to establish a closed Class A ring circuit across connected control nodes.
Operating at a fixed data transmission rate of 2400 bps, the network supports loop lengths of up to 1200 meters between neighboring panels. In a Class A ring architecture, a single open-circuit or cable break automatically reroutes communication, maintaining active peer-to-peer data interchange among up to 32 interconnected GST series control panels.
The P-9940A card is specifically engineered for full integration with GST200 series addressable fire alarm control panels, including GST200, GST200-2, and GST200N configurations, as well as the GST-NRP00 network repeater panel. Field connections require standard fire-resistant twisted pair cabling with a minimum cross-sectional area of 1.0 mm², with shielded twisted pair recommended for optimal electrical noise rejection.
For operational diagnostics, the card incorporates three onboard surface-mount LED status indicators. Red LED HL1 pulses during active communication with the panel mainboard, while green LEDs HL2 and HL3 provide continuous visual confirmation of line health across the respective master and slave transmission loops.
During installation and servicing, the host panel must be completely de-energized prior to inserting or removing the card to prevent component damage. Node recognition is confirmed during calibration mode by initiating a board reset via the SK1 key, confirming full network synchronization.

Product Information .

Hospitals, Clinics Shopping Malls, Showrooms Government Buildings, Offices Banks Airports Railways, Bus Stations Conference Rooms Auditorium Conference Hall Production Floors Construction Sites

System Compatibility, Panel Interfacing, and Network Architecture

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.

GST P-9940A Hardware Mounting, Field Wiring & Commissioning Guidelines

Cabinet Mounting and Power Precautions

The GST P-9940A Class A RS485 Network Card is an internal expansion printed circuit board assembly engineered for mounting directly within the enclosures of compatible fire alarm control panels, including the GST200, GST200-2, and GST200N series, as well as the GST-NRP00 network repeater panel. Prior to beginning hardware handling or wiring, all power to the host panel must be completely disconnected. The P-9940A card must never be inserted, connected, or removed while the host control panel is energized.

Position the P-9940A circuit board in the designated internal slot inside the panel cabinet and fix it firmly in place using mounting screws. Ensure the board is securely seated to eliminate mechanical vibration or contact with adjacent panel hardware. The installation site must maintain an ambient operating temperature between 0°C and +40°C, with a relative humidity level of 95% or lower (non-condensing).

Host Main Board Ribbon Cable Connection

Interfacing the P-9940A network card to the control panel processing architecture requires the Flat Cable HF-20 multi-pin ribbon assembly. Connect one end of the Flat Cable HF-20 to socket XS1 on the P-9940A network board. Route the ribbon cable within the enclosure and seat the opposing connector into terminal socket XS12 located on the GST 200 series panel main board. Verify that the ribbon cable connectors are fully engaged and locked before proceeding to field network wiring.

RS-485 Class A Loop Wiring Specifications

The card integrates two photoelectrically isolated RS-485 communication interfaces: Master Interface (terminals A1 and B1) and Slave Interface (terminals A2 and B2). These interfaces form a Class A closed-ring, peer-to-peer network topology supporting up to 32 interconnected GST control panels. The closed Class A loop provides redundant signal routing, ensuring continuous communication if a cable break occurs along the network path.

Loop field wiring between adjacent network nodes requires connecting the Master Interface of one control panel to the Slave Interface of the neighboring panel. Terminals A1 and B1 must wire directly to terminals A2 and B2 on the adjacent network node, maintaining strict polarity matching throughout the closed ring.

Network Parameter	Field Specification
Transmission Medium	1.0 mm² or greater twisted pair cable (shielded twisted pair recommended)
Loop Topology	RS-485 Class A closed ring (peer-to-peer)
Transmission Baud Rate	Fixed at 2400 bps
Maximum Distance Between Neighbor Nodes	Less than 1200 meters
Maximum Network Node Capacity	Up to 32 GST series control panels
Field Terminals	A1/B1 (Master Interface), A2/B2 (Slave Interface)

Panel Registration and Commissioning Sequence

After verifying the mechanical mounting, the Flat Cable HF-20 seating, and external Class A loop connections, energize the host fire alarm control panel. Enter panel calibration mode to register the P-9940A network card. Press key SK1 on the panel assembly to initiate a main board reset. If the P-9940A network card is properly interfaced and successfully registered by the panel processor, the display screen will show "Color CRT OK".

Diagnostic LED Indicators and Troubleshooting

The card includes three diagnostic LEDs to verify circuit health and identify transmission faults:

HL1 (Red LED): Main board communication status. Flashes intermittently during normal communication with the host panel main board. If HL1 does not illuminate or flash, check whether the panel has entered calibration mode; power the control panel off and then switch it on again to complete card registration.
HL2 (Green LED): Master Interface (A1B1) communication status. Illuminates steadily when the RS-485 master interface is functioning normally and no active messages are transmitting across the loop.
HL3 (Green LED): Slave Interface (A2B2) communication status. Illuminates steadily when the RS-485 slave interface is functioning normally and no active messages are transmitting across the loop.

If network messages fail to transmit between control panels, inspect the operational state of LEDs HL2 and HL3. Confirm terminal polarity across each segment (A1 to A2 and B1 to B2), inspect for open or short circuits along the Class A loop, and ensure the cable run between any two adjacent nodes does not exceed 1200 meters.

GST P-9940A Class A RS-485 Network Card Troubleshooting & Fault Diagnosis Guide

Field diagnostics and fault isolation for the GST P-9940A Class A RS-485 Network Card center on verifying internal board connections, monitoring on-board diagnostic LED indicators, confirming node addressing parameters, and maintaining physical RS-485 Class A loop integrity. The card interfaces directly with GST series control panels (including GST200, GST200-2, and GST200N) and the GST-NRP00 network repeater panel across a closed ring network architecture.

Diagnostic LED Indicators & Status Interpretation

The P-9940A card is equipped with three on-board LED indicators that convey real-time interface and hardware status. System engineers should reference these LEDs when diagnosing network dropouts or panel synchronization failures:

LED Identifier	Colour	Normal Operating State	Fault or Abnormal State
HL1	Red	Flashes continuously during active communication with the panel main board.	Remains dark or does not flash. Indicates card de-registration, calibration mode lockout, or disconnected ribbon cable.
HL2	Green	Illuminates steadily when Master Interface (A1B1) communication is normal and no packet transmission is occurring.	Remains unlit or exhibits communication anomalies during message transmission across A1B1.
HL3	Green	Illuminates steadily when Slave Interface (A2B2) communication is normal and no packet transmission is occurring.	Remains unlit or indicates loop interruption/polarity inversion on A2B2 terminals.

Main Board Interface Faults & Registration Procedures

When the red HL1 LED fails to illuminate or flash, communication between the P-9940A network card and the host fire alarm control panel main board is offline. Apply the following remediation protocol:

Power Safety Precaution: Never insert or remove the P-9940A card while the host control panel is energized. Disconnect all primary mains power and standby power before unseating or handling internal circuit board assemblies.
Ribbon Cable Continuity: Verify that the Flat Cable HF-20 multi-pin ribbon assembly is firmly seated between socket XS1 on the P-9940A card and socket XS12 on the GST200 series main board. Check for bent pins or loose headers.
Panel Calibration and Re-Registration: If the control panel enters calibration mode, cycle panel power off and power it back on to trigger hardware auto-registration. While entering calibration mode, press key SK1 to reset the main board. A successful registration of the network card is confirmed when the panel screen displays Color CRT OK.

RS-485 Class A Loop Transmission & Wiring Faults

If network messages, alarms, or status signals fail to transmit between networked nodes, inspect the RS-485 loop infrastructure according to the following engineering thresholds:

Loop Terminal Polarity: Class A networking requires alternating node-to-node interconnection. Verify that Master Interface terminal A1B1 on one panel connects to Slave Interface terminal A2B2 on the neighboring panel across the entire loop (A1 connects to A2, and B1 connects to B2). Inverted polarity between A and B leads inhibits signal decoding.
Maximum Node and Distance Limits: Ensure that the network does not exceed the maximum system limit of 32 GST series control panels. Verify that the communication cable length between two adjacent network nodes does not exceed 1200 meters at the fixed transmission rate of 2400 bps.
Transmission Cable Specifications: Ensure all network wiring utilizes fire-rated twisted-pair cable with a cross-sectional conductor area of 1.0 mm² or above. Shielded twisted pair is recommended to mitigate external electromagnetic interference.
Redundancy Diagnostics: The P-9940A uses a peer-to-peer Class A ring connection to provide redundant communication paths in the event of an open circuit or cable cut. If transmission fails completely, inspect the loop for a multiple-point cable break or simultaneous open circuits on both interface channels.

Environmental Tolerance Verification

Intermittent communication failures or electronic card lockups may occur if operating limits are breached. Verify that the ambient temperature inside the panel cabinet remains strictly within 0°C to +40°C, and ensure relative humidity does not exceed 95% (non-condensing).

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