In order to check and clear troubles on the DSC PC1555 security system you will need to enter *2 on the keypad. At that point, a totally different number should show up. Once you get this number, please document it and refer to the trouble conditions which you can find below. Also, please click the link at the bottom of the page to see the DSC trouble condition and solution guide in PDF format below. This PDF document can help you navigate the issue you are having with your panel and help you to DIY solver your problem.
Light 1 - Service Required - Press the 1 key for more info.
If the number 1 light stays on, it means the Main panel battery needs to be swapped out.
If 2 - will mean there is an open Bell Circuit,
If 3 - means General System Trouble (usually associated with Cellular/Internet Communicators),
If 4 - means General System Tamper (Open Tamper on an Expansion Board),
If 5 means Module Supervision (panel can't see enrolled keypad),
If 6 Means that a Wireless Jam has been detected,
If 7 means Expansion Board low battery,
If 8 means Expansion board A/C Failure.
Light 2 - Panel A/C (Power) Failure
Light 3 - Telephone Line trouble
Light 4 - Failure to communicate
Light 5 * - Zone Fault - Press 5 and then another light should light up. This represents what zone number is in fault.
Light 6 * - Zone Tamper - press 6 and whatever light appears is the zone that has the tamper.
Light 7 * - Wireless Device Low Battery - Press 7 once to view Wireless Zones, Press 7 again to view Handheld Keypads, and press 7 again to view Wireless Keys. Once you figure out what zone it's coming from, all you should have to do is replace the battery.
The DSC PC1555 is no longer manufactured by DSC so if you are looking to upgrade to a new alarm panel you can use one of the new DSC panels such as the DSC PC1616, PC1832 or PC1864 security systems.
DSC Powerseries PC1555 FAQ's