Programming Meridian SL1 PBX This is a short introduction into programming a Meridian PBX. The Meridian PBX's software divides information into LOADS. Each Load has a specific function. For example, LD 20 is where you can print information about phones. The loads range from LD 01 - LD 143.How to HyperTerminal into the PBX and VOICEMAIL Systems.