FREQUENTLY ASKED QUESTIONS Integrated Protection Module (IPM) Date: 8th April 2015 Version: V1R1 Author: Tapan Upmanyu How Integrated Protection Module (IPM) safeguards your PBX? Analog trunks (commonly known as CO/FXO/TWT) and analog extensions (commonly known as FXS/SLT) are widely used in telecom world. These trunk lines and cables connecting an analog phone to the PBX are generally two wire metal cables, which run over large distances covering different terrains and environments. Hence such cables exhibit vulnerability of coming in contact with power cables and lightning. Such situations will lead to passing of high voltage/current in the cables which may ultimately damage the terminal equipment. Further user will have to invest in repairing of the damaged PBX. Below given photograph shows a card damaged due to lightning/surge. To prevent such failure, it is advisable to install surge and lightning protectors. One of such device which can help to reduce the risk of damage due to the surge or lightening is IPM (Integrated Protection Module), also known as Subscriber Line Protector. IPM is inserted in the Krone module in the Main Distribution Frame (MDF). What is IPM made up of? IPM is made up of GDT (Gas Discharge Tube) and PTC (Positive Temperature Coefficient) Resistors. PTC (Positive Temperature Coefficient) Resistor for Over Current Protection. GDT(Gas Discharge Voltage Protection. Tube) How to install IPM? The below given procedure must be followed to install IPM in MDF 1. The MDF box is provided with a grounded metal strip to which ground pin of IPM is connected. Metal strips (connected to ground), to which IPM’s ground pin will be connected for Over The MDF box along with metal strips is commonly grounded using a ground wire 2. Insert the IPM in the Krone Module. 3. It is mandatory to ground the IPM from its ground pin using a metal strip in the MDF as indicated earlier. These pins will be in contact with the grounded metal strip in the MDF How IPM safeguards your PBX? There are two cases possible when IPM serves as a protection: Over Voltage Protection: High voltage comes on the line GDT gets into ON mode and prevents the voltage to enter the PBX GDT gets back to OFF mode when voltage on the line gets reduced Over Current Protection: High amount of current comes on the line PTC resistors get their contacts open and break the circuit After the current reduces on the line, we have to replace the IPM with a new one How to verify if the IPM is working or not? a. How to verify if the Positive Temperature Coefficient (PTC) Resistor in the IPM is working perfect or not? Once the PTC gets faulty you will not get dial tone on the port connected to the line because there will not be any connectivity between System & Field Cabling By following these steps it can be identified that PTC is working or not. Remove the IPM from the krone module and check if there is any dirt accumulated on the connectors. If yes, remove the dirt Check for the continuity between the Tip and Ring on the input side and Tip and Ring on the output side Tip and Ring on output side Tip and Ring on input side If continuity is there, insert the IPM back into the Krone module else replace it with a new one b. How to verify if the Gas Discharge Tube (GDT) in the IPM is working perfect or not? Certain third party equipments are available in the market to check if the GDT in IPM is working perfect or not. It is advisable that IPMs are periodically checked using such equipments. … Important It is mandatory that, the MDF box must always be equipped with IPMs. Removing IPM does not ensure that your circuit is safe from surge. After removal of IPM the system does not become an open circuit and it is not safe from surge. “PREVENTION IS BETTER THAN CURE” It is better to install IPMs and prevent your system from surge, then repairing it later on, which leads to loss of time and money. For more information, contact Matrix Technical Training Team [email protected] Disclaimer: The information contained in this document may contain confidential or privileged information. Unauthorized use, disclosure or copying is strictly prohibited and may constitute unlawful act and can possibly attract legal action, civil and/or criminal. The contents of this message need not necessarily reflect or endorse the views of Matrix Comsec Pvt Ltd on any subject matter. Any action taken or omitted in this message is not entirely at your risk and the originator of this message nor does Matrix Comsec Pvt Ltd take any responsibility or liability towards the same. If you are not the intended recipient, please notify us immediately and permanently delete the message.