The XMP1 product is multi-service access / transmission node equipment capable of PDH data rates of 8Kbps to 34Mbps and SDH STM-1 or STM-4. Originally manufactured by Marconi, the range was taken over in later years by Keymile and Bosch before being discontinued.
The system is still in service, customers include Utilities and Transport organisations, and typically deployed as a terminal multiplexer or as an ADM (Add-Drop-Mux). It can provide point to point or leased line in a corporate network for POTS, data, LAN, IDSN etc.
The building blocks of the system are the central unit which provides control and management, the SDH cards for STM-1 and STM-4 aggregation and the line units which provide uplink in the form of E1, E3 or SHDSL which can be copper or optical. 8 and 16 Slot versions were available as well as an SL (slimline) variant.
Spares and Repairs for continued long-term operation and maintenance
Whereas these products are no longer manufactured, @YellowsBestLtd is able to supply a limited amount of spare parts and/or offer repair services in order to aid customers in keeping their networks operational. There follows a non-exhaustive list of typical parts that can be supplied, we would be very pleased to receive specific requests for items that are needed.
XMP (MK2) POWER SUPPLY 48/60V
PORT HDB3 (2)
POWER SUPPLY 48-60V
CABLE CLAMP PANEL 1 HU
PATCH PANEL V.11
CCU-CENTRAL UNIT CC WITH QD2
SUBRACK XMP1 (16)
Connecting Cable 2m
Connecting Cable Central Unit Protection
Ethernet Cable (5m)
Input/Output Alarm Cable(2 O/P,3 I/P)
Connecting Cable 6m (Port HDB3) coax
Connecting Cable 20m (Port HDB2) coax
XMP1-SL CROSS CONNECT
@YellowsBestLtd our mission is in “Keeping Customers Operational”. We’re always keen to enhance our range of #business services, increase the #enterprise infrastructure we support and expand our mix of #sustainable solutions we offer for supply and maintenance of new and legacy #technologies and products for our customers.
Please help us understand your management services or solutions requirements, whether you’re implementing new systems or maintaining existing infrastructure networks to serve your operational business needs.
The Sagem ADR product range was an SDH Add-drop Multiplexer (ADM) product family designed as a flexible platform for Metro Access and Metro Core, backhauling, microwave radio and Utilities infrastructure networks.
The family included ADR155c and ADR622, STM-1/STM-4 ADM, and ADR2500 ‘eXtra’ and ADR10000, STM-16/STM-64 multi-service NG SDH. This range was managed by the IONOS Network Management System (NMS) which also managed Sagem Primary Multiplexers, PDH and SDH microwave radio and DWDM systems.
The ADR family was deployed worldwide with more than 60,000 units over 5 years.
The ADR platform offers a large variety of interfaces from E1 and E3, Fast Ethernet and Gigabit Ethernet, enabling the provision of a wide range of end Customer services. Transmission protection for guaranteed QoS is provided with SNCP, MSP, MS-SPRing as well as common unit and tributary protection.
The STM-16 network units can be used for multi STM-1 or STM-4 and local-cross connect functionality thanks to a fully non-blocking switch matrix.
The modular and flexible housing provided by the ADR155c (2U), ADR622 (6U) and ADR2500 ‘eXtra’ (14U) 19” and ETSI subracks provide a flexible mix of office, street cabinet and equipment room deployment.
Continuing to provide operational service
The ADR family of SDH products continues to provide operational service with various global Operator, Utilities and Transport companies.
@YellowsBestLtd supports requirements to maintain these networks by supplying various spare part items from refurbished and surplus stocks in perfect working order.
There follows a list of the main elements that are typically provided, though other items can be provided. Please let us know of any specific requirements you may have. We look forward to being of assistance.
The original Nokia 8110 ‘slide’ mobile phone was immortalised in the film ‘The Matrix’ in 1999.
Back then, people used mobiles for mostly … calling people, and the occasional text message. Ok, and a few plays of the game ‘snake’!
It was affectionately referred to as the ‘banana phone’ due to its unusual curved shape, though the only colour you could get it in was black.
Since then, we have had a revolution in data networking and an explosion of app-based touch-screen smartphone slates. So much so that people are finding themselves addicted to looking at these personal pocket computers ‘all the time’.
Consequently, there is now a growing trend of wanting a ‘digital detox’ and to get back to basics with a simple, cheap device that keeps you in touch without taking over your life.
The updated Nokia 8110 4G ‘Banana’ phone
In 2016, HMD Global Oy took over the licence to produce Nokia branded phones, and have since been revisiting and refreshing classic designs including their take on the ‘slide-phone’ with the 8110 4G.
As well as traditional black it’s available in bright YELLOW, making it this time the true ‘banana phone’.
With a design that harks back to those simpler days, it never-the-less comes with a number of advanced features.
What’s Good: Simple ‘Real’ number and calling keys for phoning and familiar ‘Nokia’ menu structure providing Call log, Contacts, SMS. Twin SIM cards for 4G calling flexibility at home and away. WiFi. Removable micro SD-card for expandable storage. Replaceable battery. Music Player, FM Radio and headphone jack. Camera, gallery and video player. Internet Browser and e-mail. Flashlight, Notes, Recorder, Calculator and Unit Converter. Clock and Calendar. Google Maps and directions.
What’s not-so-great: No touch-screen! Small display. Minimal App support. Fiddly ‘old school’ text-entry. Slow and limited internet capabilities. Low-resolution imaging and video, and no front-facing 2nd camera. Cursor keys surprising small and tight to bottom of display making scrolling more awkward than it ought to be. Having to take the battery out to insert / remove the memory card.
What’s Fun: Answering calls with a slide (and end them again by closing. Freedom from ‘smartphone’ addiction, though if you really must, WhatsApp, Twitter, Facebook and Youtube can just about be used. And ‘snake’ (though a strange ‘modern’ version), plus some other games and more can be downloaded.
In summary, this is a feature-packed but ‘basic’ mobile which brings an iconic design up-to-date, is fun to have, does the basics and a bit more.
Keeping connected with a digital detox
This Nokia ‘featurephone’ doesn’t pretend to rival ‘smartphones’ in capabilities. But useful as a supplementary device in case of a flat battery, and good for just keeping connected while getting on with life. Handy too when wanting to avoid carrying a very expensive piece of hardware when active or travelling.
There has been a trend to have just one device with as many functions as possible packaged in, with inevitable strain on battery life. It can however be sometimes preferable to use a Hi-Res player for music, a quality camera for photography, a tablet for internet browsing and a phone for – phoning!
So not a complete digital ‘detox’, rather just providing another alternative option to keep ‘plugged in’ to today’s ‘Matrix’ world of communications.
Your technology experiences
If you have fond memories of past technologies, views on future trends or experiences to share on managing your digital life, please get in touch. We’re keen to discuss how we may be of assistance in developing your business and keeping your new and legacy systems operational.
It can make perfect sense to continue to run existing reliable and proven systems, especially if operational requirements have not changed. Alas, the developing nature of technology means that from time-to-time, issues arise.
Changes to email encyption protocols
Modern computer communication services support the Transport Layer Security (TLS) encryption protocol. This aims to protect the information sent and received over a standard Simple Mail Transfer Protocol (SMTP) connection between two computers while ensuring that they both agree and understand the method of data transfer.
However, the earlier versions of TLS 1.0 and 1.1 have been deemed by the industry to be not secure enough and have been superseded by versions 1.2 and 1.3. You and/or your service provider may have already transitioned to the latest protocols. However, if you have old hardware running legacy software, as support from service providers is withdrawn, you may find your email stops working.
How you can tell if it’s an issue
If you’re using an Apple Mac then the Safari Browser has supported TLS 1.2 for web traffic protection since version 7 in 2013. However, if you’re still running ‘El Capitan’ OSX 10.11 with Apple Mail 9.3, it won’t support TLS 1.2 for email. Other computer hardware and software combinations may also run into problems.
Most browsers including Safari ended support for TLS 1.0 and 1.1 in March 2020, and various service providers have either already dropped or soon will withdraw operation of the older TLS protocols.
For instance, one.com will stop support of TLS 1.0 and 1.1 on 17th August 2021. Other service providers may have different end of life dates. If you’re using the one.com service then there’s an easy way to check:
Other service providers may have similar methods of verifying the protocols, so it’s worth checking with them. Failing that, you may be able to examine the headers of your emails, to look for something like this:
To ensuring your email continues to function, the options include:
Updating your operating system. In the case of Apple Mail on Mac computers, this means moving to ‘Sierra’ OSX 10.12 as Mail cannot be separately upgraded.
Using a different email client with TLS 1.2 support, e.g. Mozilla Thunderbird.
Using a browser based solution for your email
Changing your settings to send and receive email without encryption (not recommended)
Balancing New Requirements and Legacy Support
If you want to stick with your current hardware and software choices, this does present a problem, particularly if you’re otherwise happy with your setup and are unable to upgrade.
Alas if you want full compatibility (and security) with the latest industry supported functionality, whilst retaining operation of other legacy applications, consideration has to be made to invest in new hardware to run in parallel with older systems, which continue to be maintained to perform dedicated compatibility functions.
YellowsBest: Keeping Customers Operational
If you have similar or other new requirements and legacy maintenance needs, please get in touch to discuss how we may be of assistance to keep you operational.
A long time ago, great “Dinosaur beasts” of Mobile Communications were supreme. The beginnings were in the 1970’s with the launch of a Motorola handset weighing 2kg. This was followed by other barely portable products with huge batteries such as the Nokia Talkman. Only for the ‘new adopters’ who had to be in touch all the time.
Then came the ‘Bricks’
From these humble beginnings, soon a range of solid, reliable but ‘bricklike’ big and heavy phones appeared, like the Nokia 2110 and the Motorola Dynatac 8000X, as featured in the 1987 movie “Wall Street”. Designed for upwardly mobile business people.
Then came a period of rapid expansion with a diverse range of more affordable products to suit wide consumer tastes. Various forms, colours and accessories became more and more important, with slide phones like the Nokia 8110 as featured in the 1999 film “The Matrix” and flip phones like the Motorola Razr, providing a ‘Star Trek’ appeal.
An expansion of more and more features to make mobiles do more fuelled the explosion of product ranges. Cameras and music players were added to increase the functionality of these increasingly sophisticated and compact pocket-sized devices, such as the Nokia 6230.
A glance at the 2004 Carphone Warehouse catalogue shows how varied mobiles had become, with the top 10 dominated by Nokia, Sony-Ericsson, Siemens and Motorola as the biggest manufacturers of the time.
‘Tyrannosaurus’ functionality heavyweights
For a while, the king of the land was the bulky, terrifyingly expensive but impressive (for its time) Nokia Communicator, offering phone, text, email and even fax. Opening up to reveal a full QWERTY keyboard, the range started with the 9000 which appeared in the 1997 film “The Saint” and had evolved by 2007 into the even more powerful E90.
Extinction Event: The Death of the incumbents
But then came biggest shock to the world of mobile communications: the launch of the first Apple iPhone on 9th January 2007.
Like a meteorite striking the earth, this shock spelt the end for many mobile types which couldn’t compete with the sudden demand for ‘touch-screen’ devices using apps.
Indeed companies like Nokia, once the biggest of them all, couldn’t adapt and died a death, as well documented in the BBC documentary “The Rise and Fall of Nokia”
Survival of the fittest
The ‘smartphones’ from Apple and later Android-based from the likes of Samsung became an increasing hit, wiping out much diversity and seeing a seismic shift away from many form factors to the now standard “slate” style of device.
Some ‘featurephones’ as they came to be known have lingered on, and in recent years companies like HMD global, who under licence have taken some iconic Nokia designs such as the 3310 and made a successful relaunch. Diversity is now finally creeping back with new variants such as the ‘folding’ Samsung Galaxy Z Fold2.
Your Paradigm shifts
Any memories or stories to tell? @YellowsBestLtd would be keen to hear your thoughts and experiences of sudden technology ‘paradigm shifts’. Let us know if we can be of any assistance with your future solution or services requirements.
It’s almost difficult to believe that not so very long ago (ok, going back maybe more than 50 years) there were no optical fibre or digital transmission paths of any flavour of technology providing our communications infrastructure.
From early to mid 20th Century, an extensive core copper cable network was rolled out, based on analogue FDM (frequency Division Multiplexing) over coaxial pairs, with the valve-based technologies occupying a lot of space and consuming much power.
The late 1960s saw the introduction of digital PCM (Pulse Code Modulation) sampling at 8kHz. The ITU-T (International Telecommunication Union – then known as CCITT) standardised 30-channels at 64kbit/s in a 2.048Mbit/s multiplexing system, using 8-bit A-law algorithm (the USA adopted 24-channel 1.544Mbit/s with μ-law algorithm).
Problems with high bit-rates
The higher bit rates gave rise to crosstalk interference problems on many existing cables. Also, data signals transmitted as voltage levels in unipolar NRZ (Non-Return to Zero) format are not self clocking and have a significant DC component, wasting power. Bipolar RZ (Return-to-Zero) type AMI (Alternate Mark Inversion) coding prevents the build up of the DC-component for longer distance and addresses the issue of data containing multiple ones. However, long sequences of zeros still present problems with a lack of transitions causing difficulties maintaining synchronisation.
Introduction of Line Codes
Line Coding of the format mB-nB was introduced to overcome these issues. Initially 4B3T (four Binary, three Ternary) was used. This encodes each 4-bit input group into a 3 symbol output using the three states of positive, negative and no pulses.
e.g. ‘0000’ is coded as ‘+0-‘
This improved efficiency in terms of bit per symbol over AMI, which itself is an example of a 1B1T code. Improvements in transverse screened cables were also made. However, transmission problems with high-speed digital data were still encountered due to unsuitable copper cabling which needed to be addressed.
PDH Higher Order Multiplexing
By the late 1970s, the UK had adopted the ITU-T recommended PDH (Plesiochronous Digital Hierarchy) of E-carrier higher-order multiplexing at 8Mbit/s, 34Mbit/s (in the US, T-carrier at 6Mbit/s, 45Mbit/s) and 140Mbit/s.
The lower rates of the E-carrier system adopted HDB3 coding, which replaces 4 ‘0’s with ‘000V’ or ‘B00V’ (or in the US for T1, B8ZS coding which replaces 8 ‘0’s with ‘000VB0VB’).
CMI (Coded Mark Inversion) was included in the ITU-T standards for higher-order PDH at 140Mbit/s PCM (as well as SDH at 155Mbit/s electrical STM-1). This is a 1B2B type of NRZ coding where a ‘0’ is represented by ’01’ and a ‘1’ as an alternatively ’00’ and ’11’, with +V and -V representing the coding levels.
The advantage of the coding is it makes clock recovery by the receiver simple and for maintaining synchronisation alignment with a long sequence of ‘0’s or ‘1’s.
Optical fibre systems
From the beginning of the 1980s, early optical-fibre multi-mode systems operating at 850nm were deployed, and later single mode at 1300nm, using the PDH multiplexing capacities.
Typical of long-haul PDH optical-fibre systems, the 2 Mbit/s, 8 Mbit/s and 34 Mbit/s ‘Dynanet’ products from Nokia have ITU-T G.703 compliant digital interfaces using the HDB3 code, but using an optical transmission Line Code of 5B6B. This is another type of mB-nB code, where in this case 5 bit data words are coded using 6-digit code words
e.g. ‘00000’ being represented as ‘100111’.
As well as its use on electrical systems, CMI Line Coding has also been popular for use on short-haul optical-fibre transmission such as ’tactical’ fibre optical systems operating at 2 Mbit/s.
SDH / SONET – A different approach
For optical SDH systems, STM-1 and above, scrambling is employed instead of line codes to ensure the incoming bit stream contains sufficient transitions for maintaining synchronisation. This works by combining the data signal with a pseudo-random bit sequence generated by a scrambler polynomial generator.
i.e. with a sequence of length of 127, the generating polynomial is 1+x6+x7 , leading to input data ‘00000000001111111111’ being scrambled as ‘11111110000001000001’.
Optical PDH still serving
In most cases higher-order optical PDH has been decommissioned, but optical transmission at 2Mbit/s is still in operation for many low-data rate applications, where costly replacement with SDH, WDM or carrier Ethernet would bring no advantage. An example product is the Nokia DF2-8 which continues to offer reliable access services, particularly in the Utilities and Transportation industries.
Copper systems still in operation
Though core copper electrical transmission systems have now been discontinued, much of ‘last mile’ telephony and related broadband connections are still copper access. For extended data transmission applications, copper systems are still deployed and maintained. Such products include the Nokia DSL2i copper line equipment (including power feeding repeaters) using SHDSL (Single-pair High-speed Digital Subscriber Line). This uses TC-PAM (Trellis-Coded Pulse-Amplitude Modulation) which is a 4B1H Line Coding, since translates 4 binary digits into 1 Hexadecimal (16) levels. It improves range, especially when used with regenerative repeaters, and improved ADSL (Asymmetric Digital Subscriber Line) compatibility.
Feedback and assistance
This has been a necessarily very brief run-through of legacy transmission and some of the Line Codes employed. @YellowsBestLtd would be keen to hear your experiences and knowledge of transmission systems and performance of Line Codes. If we can be of any assistance with your solution requirements, including both new and legacy technologies, then please get in touch.
Continued use of Legacy Telecoms – Nokia PDH ‘Dynanet’
Public Operator and Private Network Customers across the Telecoms, Utilities, Transport and Public Safety markets maintain ‘legacy’ infrastructure for mission critical applications, which continue to deliver good operational service with high availability.
Typical products utilised are those from the ‘Dynanet’ family of PDH Transmission telecoms products, which were first introduced by Nokia over 20 years ago, and were continued in recent years by DNWP. Production of the majority of the product range was ceased in 2019.
In order to maintain these systems and networks, it’s still possible to supply spares from surplus stocks and refurbished items to keep networks operational.
Don’t forget the Connectors and Cables!
One challenge for the continued use of existing infrastructure, particularly when installing replacement parts, is sourcing the appropriate specialised and often propriety connectors for cabling of interfaces and management connections.
Regarding ‘Dynanet’, fortunately some products can still be produced, notably the Euro / SMB connectors, along with the DCN Adapter C4.0, related management software products and other items such as the TPS64 and NDUE. Listed here are a few of those currently available new:
SMB Connector for RD179 cable
Euro Connector 3×32
Euro Connector 3×7
TPS Control Unit
TPS Channel Unit
NDM DC Unit, enhanced (NDUE)
DCN Adapter C4.0
We are able additionally produce a wide range of cable products to suit most connection requirements, utilising our UK-based manufacturing partner. Bespoke cable assemblies, control boxes, harnesses, wiring looms, panels, fibre optic products are some of the network solutions available.
@YellowsBestLtd satisfies world-wide customer product sourcing requirements for current and ‘legacy’ equipment technologies from a wide range of Original Equipment Manufacturers (O.E.M.s), surplus stocks and refurbished items.
Hence, please check and if you do have any requirements, please let us know. We look forward to hearing from you.
Surplus and Refurbished Items for continued operational service
Many Customers have ‘legacy’ telecommunications networks which are continuing to provide good operational service. Particularly where functional requirements have not changed, it makes sense to avoid or delay costly and time-consuming change-out replacement projects, by obtaining spare parts.
@YellowsBestLtd satisfies world-wide customer product sourcing requirements for current and ‘legacy’ equipment technologies from a wide range of Original Equipment Manufacturers (O.E.M.s).
Stocklist of Nokia ‘Dynanet’ Spare Parts – Available for immediate supply
For the ‘Dynanet’ family of PDH Transmission telecoms products, which has provided 20+ years of service, we still have a few spare units are in stock and available for immediate supply. These items have been mostly retrieved from operational service during Customers’ decommissioning projects, and have been refurbished, tested and are warranted for working operation.
Given that production of the majority of the product range was ceased in 2019 or before, it is recommended to consider purchasing spare parts whilst there is still availability.
Here is a list of the main items currently in stock, though there may be a few additional parts that can be supplied. Hence, please check and if you do have any requirements, please let us know. We look forward to hearing from you.
DB2 2×2 Mb/s Branching Unit (B2), 75ohm
DB2 2 Mb/s Switching Unit (X2), 75ohm
DN2 2×2 Mb/s Interface Unit (IU2), 75ohm
DN2 Control Unit (CU), 75 ohm
DN2 19in Subrack
DN2 19in Subrack, grey-L91 EMC
DN2 Bus Power Unit (BPU)
DN2 Extended Bus Power Unit (EBPU)
Data Interface Unit (DIU) 2M, nx64k: G.703/704, 75ohm
Euro Connector, 3×7
Optical Teleprotection Interface Unit, C37.94
17-slot DYNANET Subrack
Subrack Power Adapter (SPA)
DCN Adapter C4.0
NDM 19in 17-slot Subrack
NDM DN2 19in 17-Slot Subrack
NDM DC Unit (NDU)
NDM DC Unit (NDUe)
NDM Ring Generator
NDM Ring Generator + DC/DC converter
NDM Backup Unit (NBU)
ACL2 RM DC Power Gen
ACL2i PF GEN Line Terminal Card
Optical Line Terminal Repeater (DF2-8), 1300 nm LED MM/SM
Optical Line Terminal Repeater (DF2-8), 1300 nm LASER SM
Optical Line Terminal Repeater (DF2-8), 1300 nm LASER LP
DM2 Multiplexing Unit, 75ohm
DM8 Multiplex Equipment, 75ohm
Ring Generator 25HZ 15W
Data Interface Unit (DIU) 48..64k, V.11, 10ch
Data Interface Unit (DIU) nx64k, V.11/V.35/X.21, 2ch
Data Interface Unit (DIU) nx64k, V.11/V.35/X.21, sync
The ‘Dynanet’ family of PDH Transmission telecoms products were first introduced by Nokia over 20 years ago, and were continued in recent years by DNWP. These have well served Public Operator and Private Network Customers across the Telecoms, Utilities, Transport and Public Safety markets with high availability mission critical infrastructure, and indeed some networks are continuing to provide good operational service.
Production of the majority of the product range was ceased in 2019. However, some products remain available to order, notably the DCN Adapter C4.0, related management software products and other items such as the TPS64, NDUE and Euro / SMB connectors.
Continued Supply of Spare Parts – Surplus and Refurbished Items
@YellowsBestLtd satisfies world-wide customer product sourcing requirements for current and ‘legacy’ equipment technologies from a wide range of Original Equipment Manufacturers (O.E.M.s).
For the ‘Dynanet’ range, we should be able to continue to supply refurbished and surplus equipment for as long as required, but the effect of the discontinuation of production is squeezing the availability of remaining stocks, with a consequential impact on pricing.
Hence, for those customers continuing to maintain their networks, it is recommended to consider purchasing spare parts whilst there is still availability. Please get in touch to advise what you need!
When phones got small (before they went big again)
In technology terms it seems a lifetime ago, now that large and ever-increasingly powerful ‘smartphones’ are commonplace, but it wasn’t so long since the trend was for mobiles to get smaller and smaller …
The evolutionary beginnings are clear, mobile phones started off as ‘bricks’: heavy, not very portable and limited in use. So the target became to make them ever smaller whilst cramming in as much functionality as possible.
The pinnacle of this development was just about reached with the Nokia 6230, a ‘feature phone’ which boasted a clock, calendar, calculator, music player, radio, photo and video cameras and a few basic games, even a limited internet browser, as well as texts and phone calls of course! A colour screen too, admittedly small (2.5cm square) and low-resolution by today’s standards, but with a battery that would last days not hours providing long talk and standby time. All squeezed into 10x4x2cm package; quite remarkable back in 2003.
This was about as small as phones got, and the small-size-format was so successful that it carried on like this for a few years, as illustrated by low-cost ‘entry’ devices such as the 2610 from 2006. Almost exactly the same size and weight, benefiting from improved screen and build but missing a camera – then still considered a ‘premium feature’, now so common place it’s hard to imagine any phone without one. Almost all of today’s phones are much wider, taller but thinner – how times have changed!
These mobile phones show off the relatively recent past of technology development, built to survive the harsh environment of the home of the Finnish manufacturer. So now, 15 or so years later – these ‘legacy’ models are still in working order, having out-lasted the company that made them!
Much has since changed in the world of mobiles, such that they’re not even used much as just ‘phones’, and Nokia’s phone business itself came and went, though now being revived by HMD Global. Despite promoting smart phones such as the ‘flagaship’ Nokia 9, it’s also interesting to see the ‘re-introduction’ of some ‘classic’ small-size-format phones, such as the 3310, harking back to those early beginnings.
@YellowsBestLtd we’re here to help #business customers maintain and keep operational “legacy” products and #enterprise equipment, as well as newer #systems, so let us know if we can assist by sourcing and supplying spares, repair and support services to ensure #technologies continue to serve and perform. Please get in touch to discuss your Management Services and Solutions requirements; we look forward to hearing from you.