Marconi XMP1 telecommunications

Traditional PDH / SDH transmission

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.  

A205HAT00080AAB05HAT00080AABXMP (MK2) POWER SUPPLY 48/60V
AN0005905762.7026.353.00-A001PORT HDB3 (2)                          
AN0009822462.7040.405.00-A001MODUL V.11                        
AN0011478462.7040.303.00-A001ETHERNET ADAPTER                  
AN0011810662.7006.430.00-A002POWER SUPPLY 48-60V                 
A2AN00034165 Cable Clamp
A2AN00086011 CABLE CLAMP PANEL 1 HU     
A2AN00086013 PATCH PANEL V.11
A2AN00102460 CCU-CENTRAL UNIT CC WITH QD2
A2AN00102463 SUBRACK XMP1 (16) 
A2AN00109256 FRONTPANEL BLUE
A2AN00116240 Connecting Cable 2m
A2AN00214510 Connecting Cable Central Unit Protection 
A2AN00214511 Ethernet Cable (5m)
A2AN0022815 DSK MODULAR
A2AN00274356 Input/Output Alarm Cable(2 O/P,3 I/P)
A2AN00276278 Connecting Cable 6m (Port HDB3) coax 
A2AN00276281 Connecting Cable 20m (Port HDB2) coax
A2AN0034165 Cable Clamp
A2AN00702802 Mounting element
A205HAN00499AAC XMP1-SL CROSS CONNECT
XMP1 spares

@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. 

#business services new legacy solutions sourcing #enterprise infrastructure #sustainable spares #technologies products @YellowsBestLtd

Repairs

Maintenance of new and legacy systems

In order to accomplish our mission of “Keeping Customers Operational”, we often assist with the repair of parts for infrastructure systems, which are typically established, long-standing and therefore proven and fit-for-purpose. It makes sense to maintain and extend the life of these systems, as wholesale replacements will be costly and disruptive. This is particularly applicable when the service requirements have not changed, so functionality upgrades are not necessary.

Often, new product spares are expensive, difficult to source with long lead times, or no longer manufactured due to the product range having been discontinued and/or the original vendor having ceased business. In such circumstances, it becomes even more important to restore existing parts to working condition, tested and warrantied.

Available hardware services vary depending on the wide range of deployed technologies, and sometimes repairs are not possible due to component shortages or poor condition of the parts (e.g. suffering from water damage). But often both ‘legacy’ and newer items can be refurbished. Rebuild and recovery of software configurations can also be required and performed.

@Yellowsbestltd would be keen to hear from you should you have any repairs requirements. We would welcome receiving any defective items you have in order to perform a no-cost assessment to establish the feasibility and likely cost of restoration. Please get in touch to let us know how we can help.

By example, there follows a list of a few recent requests we have been able to assist with. We look forward to hearing from you with any feedback you may have.

Recent repairs requests

BERMotherboard
Motherboards
LED Displayboards
PSU & Control Units
Professional CCTV cameras
Consumer Electronics
Legacy workstations
Personal Computers
Computer Software

Sagem ADR SDH family

‘Legacy’ telecoms history

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. 

ADR155c

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.

ADR622

 The ADR family was deployed worldwide with more than 60,000 units over 5 years.

Comprehensive Functionality

ADR2500 ‘eXtra’

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.

ADR10000

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.

SAGEM ADR Spares List

Part CodeUnit typeDescription
AM101333 / 251 119 665ADR155cA155 BLK STM1/4 21E1 19″/ETSI CORE CHASSIS
AM101330 / 251 137 402ADR 21E120ADR BLK BNC 21E1/120 ITFE CARD
AM101328 / 251 137 366ADR IC1.1A155 BLK FC/PC IC1.1 OPTIC STM1 CARD
251 137 410ADR LAN1A155 BLK ADRLAN 10/100BT ETH ITFE CARD
AM101360 / 251 131 182ADR FANFAN MODULE
AM101670 / 251 137 431ADR EREA155 BLK BNC ELEC STM1 ITFE CARD

New and Legacy communication issues

Challenges with maintaining Legacy systems

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:

send an email to:

protocol@tls-check.one.com.

This will provide an automated reply telling you what protocol you’re using (works with iPhones and iPads too), like this:

{
            “started”: true,
            “protocol”: “TLSv1.2”,
            “cipher”: “ECDHE-RSA-AES256-GCM-SHA384”,
            “keysize”: 256
}

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:

version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128

Solutions if you’re affected

To ensuring your email continues to function, the options include: 

  1. 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.
  2. Using a different email client with TLS 1.2 support, e.g. Mozilla Thunderbird.
  3. Using a browser based solution for your email
  4. 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.

Mobile Evolution and the Extinction Event

When Giants ruled … mobile communications

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.

Diverse expansion 

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.

Feature explosion

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.

6230
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.

2004 Carphone Warehouse “Top 10”

‘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.  

LegacySmartPhone
Nokia E90 Communicator

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.

Apple iPhone 4
Apple iPhone 4

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. 

Legacy Transmission & Line Codes

Before Fibre, there was copper!       

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.

Analogue FDM

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. 

Digital PCM

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.     

Line Coding examples

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+x, 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.

DF2-8 – TA 21518

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. 

ACL2i PF GEN – T65580

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

New Year, New Stock! ‘Dynanet’ Spares

Nokia ‘Dynanet’ PDH Transmission products

For many years, the ‘Dynanet’ family of PDH Transmission telecoms products 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.

They 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. 

Spare parts for continued operational service

@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 have recently obtained of a number of additional  refurbished and surplus equipment items. Hence, for those customers continuing to maintain their networks, there now exists the opportunity to increase stocks of spare parts to take advantage of the current availability.

Stocklist of items for immediate supply

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.

Part NumberDescription
CC 24002DB2 2×2 Mb/s Branching Unit (B2), 75ohm
B2
DB2 B2 – CC 24002
Part NumberDescription
CC 24011DB2 2 Mb/s Switching Unit (X2), 75ohm
X2
DB2 X2 – CC 24011
Part NumberDescription
CC 24101DN2 2×2 Mb/s Interface Unit (IU2), 75ohm
IU2
DN2 IU2 – CC 24101
Part NumberDescription
CC 24111DN2 Control Unit (CU), 75 ohm
CG 24170DN2 Bus Power Unit (BPU)
CG 24171DN2 Extended Bus Power Unit (EBPU)
CU 24013Data Interface Unit (DIU) 2M, nx64k: G.703/704, 75ohm
nx64k
DIU nx64k – CU 24013
Part NumberDescription
D-21470Euro Connector, 3×7
3x7
Connector 3×7 – D-21470
Part NumberDescription
D-24204Optical Teleprotection Interface Unit, C37.94
C37.94
C37.94 – D-21470
Part NumberDescription
T31094.01DCN Adapter C4.0
DCNA
DCN Adapter C4.0 – T31094.01
Part NumberDescription
T37870.01NDM 19in 17-slot Subrack
Subrack
19in Subrack – T37870.01
Part NumberDescription
T37871.01NDM DN2 19in 17-Slot Subrack
T37882.02NDM DC Unit (NDUe)
NDUe
NDUe – T37882.02
Part NumberDescription
T37885.01NDM Ring Generator
Ring Generator – T37885.01
Part NumberDescription
T37885.02NDM Ring Generator + DC/DC converter
Ring Generator – T37885.02
Part NumberDescription
T37889.01NDM Backup Unit (NBU)
NDM Backup Unit – T37889.01
Part NumberDescription
T65580.01ACL2i PF GEN Line Terminal Card
ACL2i PF GEN – T65580
Part NumberDescription
TA 21513Optical Line Terminal Repeater (DF2-8), 1300 nm LED MM/SM
TA 21516Optical Line Terminal Repeater (DF2-8), 1300 nm LASER SM
TA 21518Optical Line Terminal Repeater (DF2-8), 1300 nm LASER LP
DF2-8 – TA 21518
Part NumberDescription
TC 21101DM2 Multiplexing Unit, 75ohm
DM2
DM2 – TC 21101
Part NumberDescription
TC 21301DM8 Multiplex Equipment, 75ohm
TC 21705Supervisory Substation
TC 21710.01TMS Adapter
TU 21122.5Data Interface Unit (DIU) 48..64k, V.11, 10ch
TU 21124Data Interface Unit (DIU) nx64k, V.11/V.35/X.21, 2ch
TU 21124.05Data Interface Unit (DIU) nx64k, V.11/V.35/X.21, sync
TU 21125Data Interface Unit (DIU) 48..64k with sync, X.21
DIU X.21 – TU 21125
Part NumberDescription
TU 21205Channel Unit SUB/SUB
TU 21206Channel Unit SUB/SUB
Channel Unit Subscriber / Subscriber – TU 21206
Part NumberDescription
TU 21215Channel Unit SUB/EXCH
TU 21216Channel Unit SUB/EXCH
Channel Unit Subscriber / Exchange – TU 21216
Part NumberDescription
TU 21234.20Channel Unit E&M/VF-P, 10 ch, 20 E&M ch
TU 21236.10Channel Unit 8ch E&M/uP: 1xUKe&m/VF
VF E&M
VF E&M – TU 21236.10
Part NumberDescription
TU 21255.01Channel Switch, 4 port

Repair Services – is it B.E.R.?

Equipment repair decisions – the Customer’s right!

Customers with critical infrastructure networks have elements that fail from time-to-time. These can usually be swapped out with items from a spare parts stock, to return the system to operational service with the minimum of disruption to overall system availability. 

The question then arises of whether the failed item can be repaired. In most circumstances, it is possible to restore parts to working condition, but sometimes they are classified as ‘Beyond Economic Repair’ (B.E.R.). This can be a somewhat contentious issue.

In theory, the term should be only applied to items where the repair cost would exceed the price of the purchase of a new or refurbished replacement. However, on the one hand the term can be used to label something that physically cannot be restored e.g. due to fire or water damage. On the other, it’s often applied to items where no repair facilities exist or it’s not possible to easily source the required components to complete the remedial work. So in other words, the term is used instead of the negative-sounding ‘repair not possible’.

The reason why this can become a source of frustration is because some customers rightly insist that they should be the “one who decides” if the item is ‘B.E.R.’. Maybe for reliability statistical reasons or version compatibility, it is sometimes desired to retain the original part even if repair costs are high. Sometimes, legacy replacement spare parts are in very short supply, and so it makes sense to retain and refurbish items rather than scraping and losing them forever. Even if the short-term associated costs are greater, for products that are no longer being manufactured, the available ‘spares pool’ is finite and diminishing over time and so the decision to repair may avoid longer-term supply issues in the future.

Reduce – Reuse – Recycle

Most customers have implemented their private network infrastructure systems over a number of years, and for many their operational requirements have not changed. Consequently, it makes more sense both financially and environmentally to maintain these systems rather than embark on complete change-outs.

@YellowsBestLtd helps Customers with their operational needs, and one aspect is to #Reduce the demand for avoidable whole-scale replacements through a combination of #Reuse of refurbished spares and repair of system elements. When removal and disposal of no-longer serviceable infrastructure parts is necessary, we can also assist with the resale and #Recycle for ‘value recovery’ of valuable materials.

We can assist by supplying critical and hard-to-find spare parts and hardware repair services, even when the systems have been declared ‘obsolete’ (i.e. no longer in production) by the O.E.M. And we will endeavour to ensure that repair options are always available and the question of B.E.R. is up to the Customer to decide. Please let us know how we can help; we look forward to hearing from you.


Maintenance of Legacy networks – Spares, Connectors and Cables

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:

Part NumberDescription
21475
SMB Connector for RD179 cable
21472
Euro Connector 3×32
21470
Euro Connector 3×7
Euro Connector 3×7 – 21470
Part NumberDescription
24201TPS Control Unit
24202TPS Channel Unit
T37882.02NDM DC Unit, enhanced (NDUE)
T31094.01DCN Adapter C4.0
DCNA
DCN Adapter C4.0 – T31094.01

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.

Remaining stocks of Nokia ‘Dynanet’ spares – Update

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.

Part NumberDescription
CC 24002DB2 2×2 Mb/s Branching Unit (B2), 75ohm
CC 24011DB2 2 Mb/s Switching Unit (X2), 75ohm
CC 24101DN2 2×2 Mb/s Interface Unit (IU2), 75ohm
CC 24111DN2 Control Unit (CU), 75 ohm
CF 24186DN2 19in Subrack
CF 24186.09DN2 19in Subrack, grey-L91 EMC
CG 24170DN2 Bus Power Unit (BPU)
CG 24171DN2 Extended Bus Power Unit (EBPU)
CU 24013Data Interface Unit (DIU) 2M, nx64k: G.703/704, 75ohm
D-21470Euro Connector, 3×7
D-24204Optical Teleprotection Interface Unit, C37.94
T30506.0917-slot DYNANET Subrack
T30851.02Subrack Power Adapter (SPA)
T31094.01DCN Adapter C4.0
DCNA
DCN Adapter C4.0 – T31094.01
Part NumberDescription
T37870.01NDM 19in 17-slot Subrack
T37871.01NDM DN2 19in 17-Slot Subrack
T37882.01NDM DC Unit (NDU)
T37882.02NDM DC Unit (NDUe)
T37885.01NDM Ring Generator
Ring Generator – T37885.01
Part NumberDescription
T37885.02NDM Ring Generator + DC/DC converter
Ring Generator – T37885.02
Part NumberDescription
T37889.01NDM Backup Unit (NBU)
NDM Backup Unit – T37889.01
Part NumberDescription
T65520.01ACL2 RM DC Power Gen
T65580.01ACL2i PF GEN Line Terminal Card
ACL2i PF GEN – T65580
Part NumberDescription
TA 21513Optical Line Terminal Repeater (DF2-8), 1300 nm LED MM/SM
TA 21516Optical Line Terminal Repeater (DF2-8), 1300 nm LASER SM
TA 21518Optical Line Terminal Repeater (DF2-8), 1300 nm LASER LP
DF2-8 – TA 21518
Part NumberDescription
TC 21101DM2 Multiplexing Unit, 75ohm
TC 21301DM8 Multiplex Equipment, 75ohm
TC 21705Supervisory Substation
TC 21710.01TMS Adapter
TG 21261Ring Generator 25HZ 15W
TU 21122.5Data Interface Unit (DIU) 48..64k, V.11, 10ch
TU 21124Data Interface Unit (DIU) nx64k, V.11/V.35/X.21, 2ch
TU 21124.05Data Interface Unit (DIU) nx64k, V.11/V.35/X.21, sync
TU 21125Data Interface Unit (DIU) 48..64k with sync, X.21
DIU X.21 – TU 21125
Part NumberDescription
TU 21205Channel Unit SUB/SUB
TU 21206Channel Unit SUB/SUB
Channel Unit Subscriber / Subscriber – TU 21206
Part NumberDescription
TU 21215Channel Unit SUB/EXCH
TU 21216Channel Unit SUB/EXCH
Channel Unit Subscriber / Exchange – TU 21216
Part NumberDescription
TU 21234.20Channel Unit E&M/VF-P, 10 ch, 20 E&M ch
TU 21236.10Channel Unit 8ch E&M/uP: 2xe&m/vf
TU 21255.01Channel Switch, 4 port
TV 21640.08Power Interface Adapter DC