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 Ericsson PSTN Line Card. These cards are fast becoming practically obsolete as Subscriber Stages are being swapped out for newer technologies.The card in this picture was manufactured in week 35 of 1987 (Aug 24~28) and saw around 8448 days of active service. That is around about 23 years, 1 month, 16 days and a whopping 202,752 hours of service before it went u/s (unserviceable). A credit indeed to all those people who brought BYB202 AXE10 into existence.
Evident in this picture are the two removed RAV 13103 relays that have been replaced by a bespoke relay and daughter board solution (bottom right). Unfortunately during the repair phase the card was deemed beyond economical repair (BER) and subsequently scrapped. Luckily I had taken some snap shots of it before its BER fate.
Board Product Number: ROF 131 4382/2 R3C.
The Line Card above was housed in a Line Switch Module (LSM shelf) in a Remote Subscriber Stage (a.k.a EMG) in Denmark.
This is the abstraction layer of the SLCT3 card from an Ericsson Line Switch Module. The SLCT (Subscriber Line Circuit Test) card is one of the first cards that I ever commissioned - way back in 1988.
This image is a low resolution copy from my image library. The product code for this card is ROF 137 7852/1 R4B SLCT3.
This is the newer subscriber stage containing ALB1 LIC12s. These magazines were installed into the narrower 5 shelf racks as apposed
to the wider six shelf racks.
These racks mark the end of the BYB202 subscriber stages.
The BYB501 subscriber stages look very different. here
Above LSM product code: BFD 748 511/20 manufactured 1997W09.
Above ALB/12 product code: ROF 137 7797/2 manufactured 1997W08.
ACA3 Line Cards.
In the picture above you can see the Ericsson BYB202 Line Switch Module (LSM). Each LSM has 128 subscribers and each of the LSM modules are grouped into what is know as an Extension Module Group (EMG). Both co-located (SSS) and remote subscriber stages (RSS)
use the parameter EMG= in central software.
The shelf in the picture is LSM-0 and it sits on the C-shelf of the rack. There can be 16 LSMs to each EMG giving 2048 subscribers (16 LSM
x 128 Subscribers) per EMG. Note everything in the EMG starts at zero, hence the first LIC device, EM, LSM and even the EMG numbering starts with zero. These are some of (if not the) most widely deployed switches in the world.
Above LSM product code: BFD 328 523/36 manufactured 1991W10.
Above LIC8 product code: ROF 131 4441/2 manufactured 1990W36.
The predecessor to the BYB202 was the AXE102. In the picture above you can see the left hand side of the Subscriber Digital Magazine, or SDM magazine. Each of the subscriber cards has 4 subscriber circuits (on the top of the card position A*1F) and the 1/4 plug cable coming off the front of the card is going to the MDF. The shelf product code is BFD 329 004/4 and the line card (LIB) product codes are ROF 131 875/42.
Each shelf had 128 subscribers and on closer inspection of this picture you can see that there is a newer version of the ROF 131 875/42 LIB line card with the cable connected to the lower B*1F position. This card was manufactured in 1988.
This style of card was to be later seen on the BYB202 Line Switch Module (LSM) magazine with product code ROF 131 4441/2.
Each had 8 subscribers per card and are know as LIC8.
The other LIBs in this picture were manufactured in 1987. The oldest card in this subrack is from 1983. The build mechanics for this type of equipment are quite different from the later BYB202. In AXE102 the magazines are installed into a large frame which makes up the suite. In BYB202 build each of the magazines are mounted into racks.