Blog Archives

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 brief run-through of legacy tranmission 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

Posted in Legacy, Solutions Tagged with: , , , , , , ,
Blog Archives

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
Posted in Uncategorised Tagged with: , , , , , , , , ,
Blog Archives

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.


Posted in Legacy, Services Tagged with: , ,
Blog Archives

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.

Posted in Legacy, Solutions Tagged with: , , ,
Blog Archives

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
Posted in Legacy, News, Solutions Tagged with: , , , , , ,
Blog Archives

Legacy Telecoms Spares – Nokia ‘Dynanet’ Update

Nokia DCN Adapter – Management & Other products

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.

Nokia DCN Adapter

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!

Posted in Legacy, News, Solutions Tagged with: , , ,
Blog Archives

Legacy mobile phones – Nokia 6230 & 2610

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.

Nokia 6230

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.

Posted in Legacy, News Tagged with: , , , , ,
Blog Archives

Nokia ‘Dynanet’ PDH Telecoms Spares

Continued Supply of Spare Parts – Surplus and Refurbished Items

@YellowsBestLtd satisfies customer product sourcing requirements for current and ‘legacy’ equipment technologies.

Despite the recent ‘rampdown’ announcement by DNWP for the ‘Dynanet’ range, we should be able to continue to supply refurbished and surplus equipment for as long as required, but the likely effect of the discontinuation of production will be to squeeze the availability of remaining stocks, with a consequential impact on pricing.

Hence, it is recommended that if there is anything that might be needed, it would be best to consider purchasing it in good time to ensure availability of items and best prices.  

Here is a list of the main items immediately available from current stocks, 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
24204TPSO H/W Module
CC 24002DB2 Branching Unit, B2 2×2 Mb/s 75 ohm
CC 24011DB2 2 Mb/s Switching Unit, X2 75 ohm
CC 24101DN2 Interface Unit (IU2) 2×2 Mb/s 75 ohm
CC 24111DN2 Control Unit (CU) 75 ohm
CF 24186DN2 19″ Subrack
CF 24186.09DN2 Subrack 19″, grey-L91 EMC
CG 24170DN2 Bus Power Unit (BPU)
CG 24171Extended DN2 Bus Power Unit (EBPU)
CU 24013Data Interface Unit (DIU) 2M, nx64k: G.703/704, 75 ohm
T30506.0917-slot DYNANET Subrack
T30851.02Subrack Power Adapter (SPA)
T37870.01NDM ACM2 19in 17-slot subrack
T37871.01NDM DN2 19″ 17-Slot Subrack
T37882.01NDM DC Unit (NDUe)
T37882.02NDM DC Unit (NDUe)
T37885.01NDM Ring Generator
Ring Generator – T37885.01
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 2-8 M, 1300 nm LED MM/SM
TA 21516Optical Line Terminal Repeater 2-8 M, 1300 nm LASER SM
TC 21101DM34 Mux Card
TC 21301DM8 Multiplex Equipment, 75 ohm
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)
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 (CU) 8ch E&M/uP: 2xe&m/vf
TU 21255.01Channel Switch, 4 PORT
TV 21640.08Power Interface Adapter DC
Posted in News, Solutions Tagged with: , , , , , , , ,
Blog Archives

‘Dynanet’ Telecoms – ‘Rampdown’ notice

Phased Discontinuation of Production – 31st May 2019 – 31st January 2020

The production of the ‘Dynanet’ family of PDH Transmission telecoms products, first introduced by Nokia over 20 years ago, and continued in recent years by DNWP, is finally being ended.

This product range has 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. 

Essentially almost all the old equipment items, with a very few exceptions such as the TPS64, are being completely discontinued in a phased way according to these milestones, which have already commended:

31st May 2019 – DM8 Multiplexers, DF2-8 Optical Terminals, RPSA

31st October 2019 – DM2 Multiplexers, Subs/Exch & VF Cards, DN2 IU2, Service Terminals, V.28/V.11 DIU

31st January 2020 – DB2, DN2 CU & BPU, G.703 & V.110, DIU, Ethernet I/F, Ring Gen, NDM 19” Subrack, NDA

@YellowsBestLtd satisfies customer product sourcing requirements for current and ‘legacy’ equipment technologies.

Should you wish to read the full ‘ramp-down’ notice and know more about obtaining equipment before it is no longer available, then please get in touch.

Posted in News, Solutions Tagged with: , , , , , , , , , , ,
Blog Archives

Apple macOS 64-bit transition – Software ‘Legacy’ issues

32-bit Application compatibility Issues resulting from macOS updates

Issues have started to appear using existing and older software applications on Apple Macintosh computers with the transition from 32-bit to 64-bit operating systems, commencing with macOS High Sierra 10.13.4, and it’s set to get a whole lot worse!

Current Difficulties

Noticeable problems with applications have surfaced with the update to macOS Mojave.

Strange and unwanted things have crept in. For example:

  • opening a new Finder window causes a new tab to open instead. It’s like the wrong option has been selected – now opening a tab or a window are incorrectly identical. If you want a new Finder window, you need to then select ‘move this tab to a new window’. So suddenly this is a two-stage process 
New Finder window opens a New Tab instead
  • Trying to print from Microsoft Word causes the application to ‘crash’. The work-around for this is its still possible to print by using the toolbar button, instead of selecting ‘print’ from the drop-down menu. But then this doesn’t allow for changing print settings etc.
Microsoft Word quits when trying to print

Promise of worse compatibility problems

This is just the ‘tip of the iceberg’. A whole range of software applications which currently run happily on the Apple Mac are set to become unusable in the next update to macOS. We’re talking about mainstream applications such as Microsoft Office as well as ‘niche’ applications that you may utilise. This appears to represent the biggest shift in software compatibility since the change from Mac ‘Classic’ (OS 9 and before) to Mac OSX, more than 10 years ago.

A warning is displayed when a 32-bit application is launched in macOS High Sierra, and in macOS Mojave the alert appears every 30 days.

The official Apple advice is to ‘contact the application developer’. For the average user, that’s unlikely to achieve anything, particularly for mature applications that perhaps are no longer available or don’t have ongoing development. With something like Microsoft Word, then it should be possible to obtain the latest version, but naturally that will require a new purchase and/or an annual subscription.

Purchasing a new version of existing software will be an expensive business to just maintain your existing functionality

Maintenance Decisions

The standard maintenance advice for computers is to upgrade to the latest available version of operating software; that way, security patches are up-to-date, keeping the system secure, with new functionality as well as bug fixes provided, and support for the latest applications.

On this occasion however, it is worth taking a long considered look at the benefits of upgrading verses sticking with your current macOS release. If you haven’t yet moved to macOS High Sierra 10.13.4 or macOS Mojave 10.14 then you may wish to stay where you are for now, particularly if you’re happy with your current applications and functionality, such as Microsoft Word 2008. If you’re contemplating upgrading, either because you ‘must’ for security purposes or need to support a new generation application, then it will be worth taking the time now to review all of your existing software and work out what the upgrade path will be, or find out what the alternatives you could migrate to e.g. Apple’s ‘Pages’ to replace Microsoft Word, etc.

The most worrying situation will be for owners of specific hardware e.g. the M-Audio USB Midi interface, which may not (and never will) have a suitable updated driver software alternative

In such circumstances of uncertain application support, backups are as always essential; ideally you should be in a position to ‘roll-back’, dual-boot and/or run virtual machines to maintain previous applications and functionality. 

Consideration should also be given to maintaining a dedicated computer at the existing macOS version, and over time, migrating day-to-day applications (where they can be) to a new computer, keeping the old machine for ‘legacy support’.

Further Assistance

Take a look at the full Apple announcement about the transition to 64-bit technology and how it affects 32-bit apps.

@YellowsBestLtd satisfies new and ‘legacy’ requirements for the maintenance of systems and networks by providing services, such as technical assistance and hardware repairs, and solutions, including the supply of spare part items and software support.

We would be keen to hear from you regarding your operational needs, please get in touch.

Posted in News, Solutions Tagged with: , , , , ,
View My Stats