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.
Twenty four years to the day since I have been around AXE10. Here I am standing next to an in service APZ211*11. If I could live my life over I would join Ericsson and become an AXE10 engineer again. Two of my good friends (now passed the great divide) were part of the team that installed and commissioned this site in 1990. They done a fantastic job.
Work around enough AXE's and you will come across one of these units. These are the typical airconditioner units that are used in an exchange room containing an Ericsson AXE10 BYB202. They are made by Weatherite Building Services Ltd who have thier head office in Aldridge near Walsall.
The control panel has controls catogories for the Supply fan, Condenser Fan, Compressor #1, Compressor #2, Cooling and Heating.
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.
During my 10 years on BT Public Systems we used these keyboards to communicate with the AXE10 switches. It was on after the introduction of Windows 98 that we using laptops and desktops to talk to the switch. The tandberg terminal were so called dumb terminals. (A terminal that depends on the host computer for its processing power is called a dumb terminal or thin client)
This is a microcomputer unit from the Ericsson ROF 137 7852/1 R4B SLCT3 card. Card manufacture date is 1997 week 22.
Chip manufacturer: Motorola.
Category: 8-bit HCMOS microcomputer unit.
Introduction Technology: high-speed and low-power MCU; enhanced 16-bit timer system with four-stage programmable prescaler; power saving STOP and WAIT modes; serial peripheral interface (SPI); 256 bytes of static RAM; eight-channel 8-Bit A/D converter
Max. clock frequency: 2 MHz
This card now labeled ROF 137 1533/1 R2B/A LTC has 99W01 as its manufacturing date but a side label shows the original manufacture
date printed F3 8412 (1984 Week12 from factory F3).
I am guessing that this card started out life as an R2B and was sent back to Ericsson (or to a 3rd party) on 1999W01for modification & upgrade to R2B/A.
1984 Week12 is sometime from Monday 19th to Sunday 25th 1984.
If we decide the card was manufactured on the Monday then the approximate duration calculation results are;
From and including: Monday, 19 March 1984
To and including: Friday, 9 September 2011
Is 10,036 days from the start date to the end date, end date included.
Or 27 years, 5 months, 22 days including the end date
Alternative time units
10,036 days can be converted to one of these units:
1433 weeks (rounded down)
Yep, AXE10 is getting old!... but its still in service. The above card went down with worn out relays. It was repaired and sent back out to its site in Denmark. I hope shes in service for another 27 years!
Duration calculation by: http://www.timeanddate.com/
This is one of the old Tandberg (VT100) terminals that we used to use in order to talk to the AXE10 BYB202 PSTN switches. System X PSTN switches also used these terminals. It is what they call a dumb terminal.
We also would have had a keyboard (with a card reader attached to it) that we could swipe a pass card through so that we could access the switch.
We stopped using Tandbergs soon after Windows98 came in.
Above pictures: From my own archives.
The Ericsson AXE10 system uses address plugs that directly plug onto the cards in order to give the unit an address. The above address plug RNV 99103/20 R1A is typically used to address the Regional Processor magazines. RNV99103 also is used to address the EMRP (Extension Module Regional Processor) cards of the LSM magazines as shown in the below picture.
Product function: Address plug.
Product code: RNV99103/20.
Quarter plug: RNV304002.
Manufactured: 1998 Week 23.
Above: An EMRP card from an LSM shelf of an Ericsson RSS EMG addressed as EM-0.
EMRP: Extension Module Regional Processor.
LSM: Line Switch Module.
RSS: Remote Subscriber Stage.
EMG: Extension Module Group.
EM: Extension Module.
Picture source: My own archive.
Image source: My own library.
This is an Ericsson Line Circuit Test card. The LCT card sits in the Line Switch Module shelf (LSM). There is one LCT per shelf and they are all connected up with an 8 pair cable (two quarter plugs in a half plug cover) making a half plug bus.
Each half plug piggy-backs onto the next. The end of the bus is terminated with a resistor plug that itself piggy-backs onto the end of the bus.
Although manufactured in year 2000 this is a very old card design of AXE10 BYB202 more reminiscent of the 80s.
Function: Subscriber Line Test.
Product code: ROF 137 1533/1 R2C
Manufacture date: 2000 Week 37.
Card name: LCT (its actually on the card as LTC)
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 typical Ericsson control room from the late nineties. Earlier control rooms are easily distiguishabe as they used Tandberg (dumb) terminals for switch commuications however here we have pc terminals using windows 98. Each switch that was installed would have had a room like this and usually with the glass screen so that one could see the switch. We also enjoyed using laptops which made our life much easier having all of our software tools at our fingertips wherever we went.
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.
Part Number: MT4LC16M4T8
Chip Type: 16 Mb x 4 MICRON FPM DRAM
Availability: Obsolete since year 1999.
Before the more modern forms of Dynamic Random Access Memory (DRAM), Fast Page Mode DRAM (FPM) was the most common kind of DRAM in computers. What Page Mode DRAM does is it accesses a complete row of RAM without having to constantly re-specify the row.
There after a Row Access Strobe signal (RAS signal) is kept active while the Column Access Strobe signal (CAS signal) changes to read a sequence of neighboring memory cells.
This reduces the access time and lowers the power requirements. Clock timings for FPM DRAM are typically 6-3-3-3 (meaning 3 clock cycles for access setup, and 3 clock cycles for the first and each of three successive accesses, based on the initial setup).
T8 - Re-fresh addressing of 4,096 (4k) rows.
DJ - Plastic package. Pin Assignment. 32-pin SOJ (400 mil).
-5D - Timing. 50ns access.
9910 - Manufacture date of 1999, week 10.
MT - Micron Technology, Inc.
4LC16M4T8 - Product code.
I-I - Unknown.
YVT6 - Unknown.
The 16 Meg x4 DRAMs are high speed CMOS dynamic random access memory devices containing 67,108,864 bits organized in a x4 configuration. The MT4LC16M4T8 is functionally organized as 16,777,216 locations containing four bits each.
The 16,777,216 memory locations are arrainged in 4,096 rows by 4.096 columns.
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.