Yes, The DSC PC1555 security system can use wireless sensors you need to make sure that you have a compatible wireless receiver for this unit which is the  DSC  RF5132-433. Once you have added this wireless receiver you now have successfully turned your DSC Pc1555 wired system into a hybrid security system meaning you can use both hardwired security sensors and wireless RF sensors.

 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

DSC Powerseries PC1555 Alarm Monitoring Options