Peripheral Expansion Module

Peripheral Expansion Modules (or PEMs) were large expansion boxes that could be attached to the side of some Olivetti computers. Pretty much nothing is known about them. How they were connected to the computer, and exactly what computers could use them, is a mystery. PEMs were made for the Second Style XP 1078 (scroll down a bit...) computers, LSX 5015/5030 computers, SNX computers and NetStrada computers. And now, some info and pictures...

Second Style XP 1078 PEM
According to an ad found in an old newspaper, these PEMs increased the system's maximum RAM capacity to 256 MB and increased the system's maximum storage capacity to 31,3 GB. The ad also seems to imply that these PEMs contained an SPS (Standby Power Supply) that could last for 10 minutes. They appeared to have a round power button, a power? light and another light next to it. It is unknown what the second light was for and what color it was due to the lack of good pictures.

LSX 5015/5030 PEM
Those PEMs were made for use with the LSX 5015 and LSX 5030 computers. They have a round power? button at the bottom right, a power light, and a light next to that (it is unknown what that light represents).

Olivetti PEM 100/R (systema?)
According to the Pocket Service Guide for the following computers, these PEMs could be used on the Olivetti SNX 140, 140/R, 160, 160E and 160/R systema. The "R" in "PEM 100/R" stands for "Resilience". According to the Pocket Service Guide, they were used to increase the number of hard drives a system could use. The hard drives could only be hot-swapped if the PEM was connected to an SCSI RAID controller. If the PEM was connected to another type of SCSI controller (non-RAID), the hard drives in the PEM were merely considered as expansions. Up to three PEMs could be connected to a system. According to the Pocket Service Guide, these PEMs might've had an optional console with a display which would show any error messages encountered, and then prompt the user to press "Enter" to continue to attempt to solve the problem. If the system was configured as "Remote Terminal" or with "None" and the video and keyboard were not connected, no error message would've appeared. The console also had a  SYS FAULT LED which would light up when the swap board they were connected to detected any abnormal temperature readings in the circuit boards and disk areas (only if the  Resilience Support drivers were installed).

A PEM for the big LSX 3000 systems?
This picture of an Olivetti LSX 3020 shows the system with a large box attached on its side... Could it be a PEM?