1. Product Introduction: This product is suitable for indoor and outdoor card-type public payphone units, industrial waterproof telephones, and explosion-proof telephone units. Due to our company's excellent material selection, meticulous processing, strict testing, and the diversity of main structural components, this product is bound to meet customer selection requirements.

2. Compliance Standards:
GB/T15279—94 Technical Conditions for Automatic Telephones
GB/T2423.17—1993 Basic Environmental Testing Procedures for Electric and Electronic Products, Test Ka: Salt Spray Test
YDN109-1998 Part 4 Technical Requirements and Testing Methods for IC Card Telephones
Q/SX102—1999 Detailed Specification for Handset Assemblies of Card-Type Public Payphones

3. Operating Environment:
Ambient Temperature: -25℃ to 55℃
Relative Humidity: 10% to 95%
Atmospheric Pressure: 86 to 106 kPa
Ambient Noise: ≤60 dB(A)

4. Main Structural Components:
4.1 Handset: Made from GE Plastic PC/ABS C2950 alloy plastic through injection molding, with a fire resistance rating compliant with UL-94V-2 specifications. Available options include 500# (210mm long) black glossy and matte round handsets, and 600# (220mm long) black glossy large round handsets for customer selection.
4.2 Tail Sleeve: Available in blue and black plastic tail sleeves, as well as polished chrome-plated copper tail sleeves for customer selection.
4.3 Flexible Hose: Made from SUS304 standard stainless steel strip with a thickness of 0.22mm. Axial tensile strength ≥1200N, with bending radius, flexibility, and elasticity compliant with MS20 requirements.
4.4 Steel Cable: ф1.8, minimum breaking force of 280Kg, with the corresponding tensile strength of the handset assembly >250Kg.
4.5 Conductor: Available in 4-core/6-core TEFLON or PVC sheathed wire compliant with UL-94V-2 specifications, selected according to customer requirements. Conductor cross-section is 0.2mm2, and length is determined by customer requirements.
4.6 Transmitter/Receiver:
4.6.1 Transmitter: Uses a moving-coil receiver SD150T with an impedance of 150Ω, (at 1KHz, 60mV input) 97±2 dB SPL (at 1KHz, 0dBSPL = 20μPa) Input 60mVrms, with B&K artificial ear 4153.
4.6.2 Omnidirectional Electret Condenser Microphone: Voltage 3.0V-10V, impedance 2.2K, sensitivity (-28 to -46) dB, 0dB=1V/Pa at 1KHz.
4.6.3 Receiver: Uses moving-coil receiver ST150T with an impedance of 150Ω, and moving-coil receiver SD150TH (with hearing aid performance) impedance 150Ω, (at 1KHz, 60mV input) 97±2 dB SPL (at 1KHz, 0dBSPL = 20μPa) Input 60mVrms, with B&K artificial ear 4153.
4.7 Connector: The conductor lead-out method and connector selection are specified by the customer.
4.8 Ground Wire: Installation of a ground wire, as well as the wire gauge, length, color, and terminal type, are determined by customer requirements.
4.9 Flexible Hook Switch: If the unit adopts a flexible hook switch form, magnetic steel or reed tubes can be installed according to customer requirements.
5. Technical Performance:
5.1 Transmission Performance: After connecting the handset assembly to the main unit and accessing the analog telephone network test system, the sending and receiving loudness ratings and sidetone masking ratings comply with the requirements of GB/T15279-94 (see Table 1) or specific customer requirements: