Note: This article details POS, Analog TTY, and other services sending data over an analog connection.It is not common for SkySwitch resellers to connect a SIP Analog Adapter to an alarm panel or credit card terminal and expect the system to work.In the case of Credit Card Terminals, we recommend contacting the merchant processing company and requesting an IP-based Credit Card Terminal.However, using any VOIP service and Alarm Systems can pose problems because an alarm system is designed to send its signals over an analog phone line. To transmit emergency signals properly using VOIP, the signal must be converted to digital, then converted again to analog. It is during this conversion that problems develop. Usually the signals arrive at the central monitoring station with errors (dues to latency, jitter or packet loss), or not at all.Knowing this, some alarm companies have taken steps to try to make their transmissions more reliable. These include sending the same data up to 8 times to maximize the chances that it is transmitted successfully.Additionally, for modern alarm systems, there are two formats used for transmitting information from an alarm system to the central monitoring station: SIA and Contact ID. It has been said that the SIA format works more successfully with VOIP than the Contact ID format. Contact ID pre-dates SIA and is therefore more widespread in use. SIA stands for Security Industry Association and is the newer universal standard for alarm communication. Therefore, alarm companies will often ensure that customer premise equipment is SIA compatible if they know that VoIP will be used.As a result, it is highly advisable to consult with the alarm company before providing any type of alarm service over VoIP.Remember, no system is perfect. It’s imperative to thoroughly test the alarm system over the new VOIP system repeating the test many times to achieve a statistical significance ascertaining expected reliability (reliability = successful transmissions ÷ total transmissions).