The above picture shows rows of Line Switch Modules (LSM's) neatly lined up awaiting their fate. This scene reminds me of what it looked like when we were installing the AXE switches. Sadly, this once busy switch is now being dismantled with its subscribers and their traffic already having been migrated to a Next Generation (Voice over IP) based node. The above AXE10 was a fantastic switch and carried traffic in service for over 20 years without any outages.
This is an alarm panel from the 80's and 90's generations of BYB202 AXE10. Easy to interperate with A1 and A2 class for the APZ (processor), APT (switching), POWer and EXTernal alarms.
O1 and O2 are Observation alarm classes.
ATT is for ATTendance activated by command by AXE personnel when on site (site attendance).
The white gas mask shaped things are acually speakers and beep when there is an alarm.
TYN and MAN are the names of the sites this panel serves.
IOG 11 belongs to what is called an SP-based IO System.
SP is an abbreviation for Support Processor. It is the separate processor that control the IO system functions, for example. the hard disks, optical disks, floppy disks and all the Alpha numemric (AT) terminals, later called Local Craft Terminals (LCT's) and all other communication links between the AXE and humans or other computer systems. i.e. X25/V36 protocol links.
Several variants of the SP-based IO Systems existed including IOG 11A, IOG 11B, IOG 11C, IOG 11B5, IOG 11C5 and IOMC.
The 2-20, as it was called, is a pair of CP racks that work in parallel synchronous and at any one time either the A-side rack or the B-side rack would be the Executive side (handling the traffic) and the other side would be in active standby ready to take the traffic should the Executive side fail.It was easy to see who was who as there are indicator lights at the top of each rack. I would be surprised if there are many (or any) of these still in service? If you know of one please let me know.Top Shelf: Fans for cooling.
Second shelf down: the CPU shelf itself.
Third shelf down: RP bus magazine and tall blanking plate where the maintenance unit (MAU) would be if this was a B-side processor rack.
Bottom shelf: RP bus magazine.
The little green light on top of the rack indicates that this rack is the Executive processor, the processor that is primarily handling the traffic being switched at the time of taking this picture. The blanking plates were always used to increase the cooling efficiency.
This is a STU card from an APZ212*20. This particular card came out of the B-side CPU from a switch in London. It has no less than 80 16Mb DRAM chips configured into banks of 10. In my next post I will give a description of the 16Mb DRAM chips.
Board Product Number: ROF 157 1035/1 R2A STU.
Manufacture Date: 99W31.