Legacy Serial Communications Protocols 

Modern networking standardisation

For decades, various communication protocols have been utilised to connect telecommunications and computer hardware devices over short and long distances. To avoid incompatibility problems, standards were formulated and agreed, but meanwhile, a continuous drive to provide improved performance has meant an evolution of various alternatives.

Today with the dominance of USB, there are connector types and associated data protocols that have become almost universal for the wired serial connection of new devices over short-distances (when the use of wireless alternatives like WiFi and Bluetooth are not possible or appropriate). Whilst Ethernet has become the preference for local IT networks, for long-distance telecommunications, fibre-optic transmission is providing the benefits of reliable high bandwidth services. 

Maintenance of legacy standards for connecting and communicating 

Despite this, many older infrastructure systems and devices continue to utilise historic protocols and connections, and so it is still of benefit to recognise and be able to maintain ways to interoperate. There follows a non-exhaustive overview and comparison of the most popular standards and types of serial data communication methods.

RS-232 (V.24 / V.28)

Introduced way back in 1960 by the Electronic Industries Alliance (EIA), this is probably the longest surviving communications standard, but over time due to various revisions and lack of uniformity of connector types and connections, incompatibilities can arise. This resulted in the need for conversion cables, gender changers, etc.

It is a serial, full-duplex, unbalanced, single ended communications standard which has limitations in terms of transmission distance, noise immunity and operating speed, and can only be used for point-to-point connections.      

Given its age, it pre-dates most of modern computing, and was established for the relatively new purpose of communicating between a teleprinter, designated as the Data Terminal Equipment (DTE) and a modem, the Data Communication Equipment (DCE). The standard defines a range of ‘circuits’ (pin assignments) which include data – TxD (transmit) and RxD (receive) – along with various control signals such as DTR (data terminal ready), RTS (request to send) and CTS (clear to send).

When directly connecting two DTEs, such as two computers without using modems, a ‘null modem’  or cross-over cable is needed to swap the connections between the transmit / receive data and control lines.

Over the years, this extended to the uses of connecting computers to various peripheral devices like printers, as well as to other computers. Most PCs then came to be equipped with a “D-Type” port, initially for 25-pin connectors but eventually 9-pin became much more common.

Voltage levels are defined for the signals, in the range of -3V to -15V i.e. negative voltage representing a logic ‘1’ (mark) and between +3V to +15V i.e. positive voltage as logic ‘0’ (space). The range between -3V and +3V as invalid, and typically voltages are expected between +/5V to +/-12V whilst peak voltages can up to +/- 25V.

RS-232 TTL

This variant to the RS-232 standard is designed for more convenient interoperation with low voltage circuits over shorter transmission ranges. This specifies a positive voltage of +5V representing logic ‘1’, and 0V for logic ‘0’, which unfortunately can cause operational difficulties through confusion regarding the deployed types. Naturally, this requires correct interfacing and use of converters to provide the required voltage level shifting and inversion between variants.

RS-423 (V.10 / X.26)

Originally designed and launched in 1975 as a replacement for RS-232, offering longer distance and faster speed communication, it failed to become widely adopted. It did however feature on the BBC Micro in the 1980s, utilising an unusual 5-pin DIN connector.

Sharing similarities with RS-232 as a serial, full-duplex, unbalanced, single ended communications standard, it notably adds multi-drop capability, making it possible for one transmitter to send data to up to 10 receivers.  It’s voltage range is restricted to +/- 6V, with the driver output between +3.6V to +6V representing logic ‘0’ and -3.6V to -6V for a logic ‘1’.

RS-422 (V.11 / X.21)

This standard, also launched in 1975, provides serial, simplex, balanced, differential communications. Like RS-423 it provides multi-drop capability for one transmitter and 10 receivers.

It was more successful as an upgrade to RS-232 as it provided better noise immunity through the use of twisted pairs of conductors carrying two differential data lines. Full-duplex communication is provided by using 4 wires and two transmitters and two receivers to send the data in both directions.

The differential voltage between the pair of transmit lines and pair of receive lines determine the logic states, rather than the nominal 0V to 5V signals compared to ground, with the maximum common-mode voltage in the range +/-7V.

Typically, line A (or Y) is labeled TxD- / RxD- and is the non-inverted signal and line B (or Z) is TxD+ / RxD+, which is the inverted or complement of the same signal. Then B greater than A usually represents logic ‘1’, following the RS232 convention that this state is represented by a negative voltage, in this case line A of at least less than -0.2V with respect to B. Conversely, A higher than B by at least more than +0.2V, therefore represents logic ‘0’.

It is important to assign these lines correctly; for instance, on a Nokia DM2 multiplexer, the UR / UT specifications for the MI service interface assign logic ‘1’ to a negative voltage, but this doesn’t make it clear whether this is referring to B >A or A > B. In practice, this can be addressed simply by reversing the two input and/or the two output A & B connections should the opposite assignment apply.       

RS-485

This standard came out in 1983, and brings further enhancements over RS-232 whilst retaining a degree of backwards compatibility with RS-422. It provides serial, semi-duplex, balanced, differential communications. Like RS-422 it uses twisted pairs of differential data lines to provide improvements to transmission distance, noise immunity and operating speed. But through use of bidirectional transceivers, it only requires 2 wires to provide both directions of data transfer (though not at the same time, i.e. semi-duplex).

This can be upgraded to 4 wire full-duplex operation by adding an additional pair of transceivers, but in practice this is not necessary unless for interworking with existing RS-422 components. It extends transmission capability to true multi-point communication, with the possibility for use of up to 32 transmitters and 32 receivers, by means of a tristate mode so that drivers are switched off when not transmitting.    

Usually, line A is named D- as the non-inverting signal and line B is its complement, the inverted signal named D+, such that when the voltage of D+ is high, D- is low. With B greater than A by +0.2V then this represents logic ‘1’. The opposite polarity, resulting in a voltage difference of B lower than A by -0.2V, is therefore logic ‘0’.

Its improved maximum common-mode voltage range of -7V to +12V aids its ability to operate in multi-point configurations, allowing for wider differences in ground potential between the drivers and receivers.              

Conversion between RS-422 and RS-232

This naturally loses the RS422 advantages of differential data for noise suppression and transmission distance.

For RS232 a negative voltage is logic ‘1’; when the device transmits this to the RS422 RxD- or A input the differential voltage with respect the RxD+ or B input held at GND is B > A i.e. logic ‘1’. Whereas with a positive voltage from the RS232 device the RS422 input differential voltage is A > B, equating to logic ‘0’. 

However, when the RS422 TxD- or A output is low it could be the case that this not as negative a voltage as the -3V the RS232 device is expecting, and so technically is invalid according to the specification. However, in practice for many devices their operating threshold is beyond -1.5V and since B > A it is interpreted anyway as logic ‘1’. When the RS422 TxD- or A output is high, A > B which results in logic ‘0’ at the RS232 receiver.

Interconnection of  RS-485 and RS-422

Since RS-485 transceivers are generally ‘backwards compatible’, they can be applied to interface with existing RS422 devices. For full-duplex communication, 2 transceivers are used in the 4-wire configuration of RS422, and the semi-duplex capabilities of RS485 are ignored. Plus the RS422 restrictions of only one driver and up to 10 receivers per transmission direction apply. 

The RS422 driver TxD+ and TxD- lines are respectively connected to the D+ and D- pins of a RS-485 device acting as a receiver. Similarly, the D+ and D- pins of a RS485 device acting as transmitter are connected to the RxD+ and RxD- lines of the RS422 receiver(s). 

Comparison with USB

Whilst USB has become the De Facto standard for modern short distance wired connections, it is useful to compare this against the legacy protocols in order to understand the similarities and differences, and why it may be important to maintain or even extend existing interconnections.

USB 1.0 / 2.0 provide serial, semi-duplex, balanced, differential communications, analogous to RS-485 whilst offering much faster communication packaged in a smaller and more convenient 4-pin form-factor.

USB 3.0 uses two additional pairs of conductors in a compact 9-pin connector to operate full-duplex like RS-422, whilst maintaining backwards compatibility with older USB connections, and provides various further improvements including even faster ‘SuperSpeed’ transmission. 

However, USB only provides for point-to-point connections, with lower power and limited to TTL voltage levels, and as a result shorter transmission distances.

In conclusion, the choice of use depends on the various differing applications such as the interconnection of computer peripherals, industrial control, remote monitoring and multi-device connections. 

Consequently, for legacy interworking and improved performance over longer transmission distances with wider voltage ranges, dedicated USB to RS-232 / RS-423 / RS-422 / RS-485 converters are available.

Keeping Customers Operational

@YellowsBestLtd with our aim of Keeping Customers Operational assist with seeking out new products and legacy equipment spares to maintain new and well-established systems, as well as built-to-order cables and connectors to suit exact requirements.

We would be keen to hear your experiences of using communications protocols and whether we can be of any assistance with your solution requirements for legacy systems and new technologies, so please get in touch!

Hardware Repairs

Organisations that deploy, own and maintain infrastructure systems and networks make considerable investments in time and money, and it makes complete business sense to maximise the return on these investments. Even if it were desirable to make wholesale replacements, such projects take time to undertake. Ideally, if the equipment is performing satisfactorily and operational requirements have not changed, then is better to keep the existing equipment maintained for as long as possible.

Critical infrastructure systems are typically built to last, with high availability and reliable system components, and interchangeable spare parts. But sooner or later, repairs to elements are needed. During initial deployment and warranty periods, this is not normally an issue, but over time, these services become more specialised and difficult to obtain, as vendors advance their portfolios and discontinue older products.

@YellowsBestLtd specialises in ‘Keeping Customers Operational‘ by sourcing equipment spare parts and hardware repairs to modern and legacy systems. Should you have any requirements, please get in touch; we would be very pleased to hear from you, and look forward to being of assistance.

Take a look at some of the elements for which we provide hardware repairs services: Recent repairs requests

Ultrafast Fibre Broadband – ‘FTTP’

Although the installation of fibre broadband services have been rolling out across the UK for some time now, there still seems much confusion relating to the various services on offer.

@YellowsBestLtd has been receiving ‘Fibre To The Premises’ (FTTP – sometimes referred to as ‘Fibre To The Home’ FTTH) from @Gigaclear since our formation in 2015. We are therefore able to provide this brief summary of our experiences and comparison of the types possible and their capabilities:

Full Fibre (FTTP) – fibre runs directly to the office or house, giving the fastest and most reliable speeds. This is what we had installed by Gigaclear; a dedicated fibre line into a fibre modem which can be directly connected to using ethernet cable or via a wifi router.

Part Fibre or ‘Fibre to the Cabinet’ (FTTC) – fibre runs to the neighbourhood cabinet, and then data runs over copper lines into the building. The transmission speed and bandwidth is therefore reduced in comparison to Full Fibre. This is the type of on offer to many consumers where the local telephony provider is not able to rollout fibre replacement for the ‘last mile’ of copper connection.

Copper or non-fibre – the traditional, existing telephone lines are used to provide the broadband service. This naturally provides the slowest speed and least data bandwidth. Many communities still rely on this as the only means of internet connection, since no fibre broadband deployment has been made.

The net result is that with Full Fibre, it is possible to receive previously unheard of speeds. Indeed the maximum service on offer is so fast, it outstrips the requirements of most homes and businesses. It is therefore typical that a reduced service is selected purely for cost-saving purposes.

Our own experiences have found that the Ultrafast 300 service from Gigaclear to be more than adequate for our needs. This is a screen shot of an actual speed test of the service we are being provided with:

In many cases the ‘full fibre’ service we have chosen, approximately a third the speed of the maximum possible, is still at least 10x faster than part or no fibre services. Not only is it faster, it provides a very stable connection less prone to interference and service outages. Thought due to network backhauling connections, is not unknown for interruptions to be possible; fortunately these are relatively rare.

The main difficulty for most businesses and homes remains the lack of universal provision. Whereas we have no reservations in recommending Gigaclear’s full-fibre service, we recognise this is not available everywhere. It is just fortunate for us that rural communities like ours was prioritised in their initial service rollout.

@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 get in touch to 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. 

Challenging times demand time for a change!

New “UK” launch

It’s been a challenging time for businesses generally, and particularly in the United Kingdom, with Brexit in many cases adding cost and time to trading, and Covid-19 restricting travel and networking.

So it seemed an appropriate time to launch a new varient of the Yellows Best Limited website, now additionally utilising “.co.uk” as a signifier of commitment to our home market location.  

Keeping Customers Operational

The new YellowsBest.co.uk promotes the same blend of Services and Solutions for “Keeping Customers Operational”, but presented in a different and modern single-page layout, making it particularly mobile device-friendly where ‘vertical scrolling’ is more appealing than using the traditional ‘horizontal tabbed’ layout.

We hope this provides Customers old and new with a welcome alternative, though the original YellowsBest.com will continue to be maintained, along with it’s associated blog for ‘informal’ views and news updates.

Assisting with your requirements

It would be interesting to receive feedback as to how useful you may find this additional site, and whether there is anything else you’d like to see featured.

Of course, @YellowsBestLtd online content ultimately serves the purpose of highlighting the types of services and solutions we can provide. Customers may therefore be prompted to get in touch to discuss their specific requirements, which we can usually assist with.

Rest assured, if you use either contact address:

enquiries@yellowsbest.co.uk

enquiries@yellowsbest.com

we’ll receive your message and will be in touch by return. We look forward to hearing from you! 

Repair Services

Maintenance Services for Systems Equipment

From time-to-time, hardware elements within infrastructure systems fail, and repair services are required for a diverse range of parts procured over a considerable period of time, from a multitude of Original Equipment Manufacturers (O.E.M.s), some of which no longer exist.  

YellowsBest is able to provide a comprehensive repairs management service for both new and old equipment items, all to a standard equivalent to the original working condition and with warranted operation.

Component Level Repairs Example: SES Displayboards 

An example of the type of equipment that we are often asked to assist with is the MS1 Matrix LED ‘displayboards’ produced by SES and used for professional signage applications.

LED ‘displayboards’

Typical issues to deal with are Faulty LEDs, damaged capacitors and broken sockets, which have occurred in operational use over time. Adding to this are problems stemming from heat gun damage and resoldering caused by previous ‘user fixes’.  But these issues are addressable and the boards restored to full working condition. 

Other types of equipment for repair services include Telecommunications products, power supplies and CCTV cameras.

Repairs
Typical Items for Repair Services

Reduce – Reuse – Recycle

@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.

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. 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. We look forward to hearing from you.

‘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.

Keymile UMUX – Multiservice access solutions

Comprehensive Functionality

The UMUX platform provides carrier-grade reliable multi-service multiplexing and aggregation functions over copper and fibre networks. A variety of voice (POTS, FSX, FSO, ISDN) and data (e.g. G.703, V.11, V,24, V,35) interfaces, SHDSL and Ethernet (including PoE+ and EoS) services are available. 

The modular and flexible housing provided by the UMUX 1500 (8U, 21-slot) and UMUX 1200 (4U, 8-slot) 19” subracks provide the perfect solution for all applications and locations, offering redundant controller and power supplies.

‘Legacy’ telecoms history

The UMUX SDH product portfolio was originally launched 1991 by Ascom, which subsequently became Keymile.

In 2003, by when 70,000 units had been deployed worldwide, the ‘enhanced’ UMUX multiservice access platform was introduced, offering the delivery of ATM, TDM and IP based services from the same platform, with support for IP/Ethernet, ADSL, VoDSL and G.SHDL.

Keymile was sold to ABB in 2017 when the UMUX range was discontinued, and then was acquired in 2019 by DZS. 

Continuing to provide operational service

The UMUX, together with the UNEM network management system and ‘sister’ LINERUNNER and MILEGATE 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.

Part CodeUnit typeDescription
A31A1679U1500-CSU1500 Core R2 (DC) for 19″ mounting (incl. Subrack, POSUM, COBUX 128x2Mb/s XC)
A30A0205DATAS-FUData Interface unit.  Multi-Interface V.35, V.24/V.28, X.24/V.11, RS485, Ethernet, 4 ports, all options
A24A3323LOMIF-FU2 Mb/s IF (E1), 8 x G.703 Interfaces
A24A3651COBUX-FUControl Unit Standard,128x2Mb/s XC
A21A2865EXLAN342POTS FxO Interface Unit, 12 ports, complex impedance
A31A7871GECOD371Data IF 64kb/s G.703 codir., 8 interfaces
A24A3338LOMI4-FU2 Mb/s IF (E1), 4 x G.703 Interfaces
A24A7979POSUM306Power supply unit -48VDC 85W
A30A1442SUBH3-FUPOTS FxS  Interface Unit, 30 ports
A31A7873SULIS393ISDN Interface Unit Subscriber side, ISDN BA 2B1Q, 8 interfaces
A23A9927SYNAC-FUSDH Access bridging unit SBUS-PBUS, 8xVC-12; no external IF
A24A1989TUPON-FUOptical Trunk Interface 8Mbit/s 1xopt.(o), 4xel.(e), 1550nm, PBUS access


Nokia ‘Dynanet’ Telecoms – Stock disposal

‘Last chance’ for spares!

The Nokia ‘Dynanet’ family of PDH Transmission telecoms products has served customers well for the last 20+ years, and indeed some networks continue providing good operational service. 

DM2
Dynanet Subtrack

@YellowsBestLtd has supported requirements to maintain these networks by supplying various spare part items from refurbished and surplus stocks in perfectly working order.

However, demand has recently reduced and warehouse space is needed, so now the time has come to recycle / dispose of a large proportion of the remaining equipment. Consequently, there remains a short-term opportunity to obtain any items still required to maintain existing deployed infrastructure, before the products are gone.

Here is a stock list of the main items currently available, 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 – before it’s too late! 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
T37889.01NDM Backup Unit (NBU)
T65520.01ACL2 RM DC Power Gen
T65580.01ACL2i PF GEN Line Terminal Card
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
TU 21205Channel Unit SUB/SUB
TU 21206Channel Unit SUB/SUB
TU 21215Channel Unit SUB/EXCH
TU 21216Channel Unit SUB/EXCH
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

Three years milestone

Three years completed; onward in our fourth year!

@YellowsBestLtd has now reached the significant milestone of completing three years of trading; something often useful to be able to state when qualifying for opportunities and registering with business customers.

Our aim continues to be “Keeping Customers Operational”; understanding requirements and fulfilling them by providing a range of management services and solutions, including:

  • consultancy, such as business development planning3_years_services
  • technical support, e.g. day-rate engineering, NMS assistance
  • systems supply, including legacy IT servers / workstations
  • spares for infrastructure, in particular telecoms and CCTV cameras
  • repairs at module and component level, e.g. LED displayboards
  • value recovery through reverse logistics, resale and recycling

As we move forward in year four, we’d very much like to discover what else to provide to our existing Customers, as well as what would be of interest to potential clients. 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.

Please get in touch to discuss your challenges; whether you’re implementing new systems or maintaining existing infrastructure to serve your operational business needs. We look forward to hearing from you.

Keeping Customers Operational – ‘telling’ not ‘selling’

@YellowsBestLtd our mission is to provide our Customers with Management Services and Solutions so their infrastructure networks continue to serve and perform – “Keeping Customers Operational

Needs vary from the launch of the latest IT and Telecoms technologies through to the support of well-established legacy systems.

Given that each organisation is unique, both in its business practices and deployed infrastructure, then we find that its best to take a flexible approach and provide tailored services to suit exacting demands.

Our no-cost and no-obligation Customer consultation is all about finding out needs, regardless of technology or manufacturer, and then sourcing the required solution(s), which may mean seeking out difficult to obtain products or requiring the supply of specialist services.  So in essence, it’s not about us ‘selling’ them something we have, but rather our clients ‘telling’ us what to provide. Making it easier and more convenient for busy procurement and operational teams,  saving them effort, time and cost.

We’re always keen to see how we can enhance our range of #business services, increase the #enterprise infrastructure we support and expand our mix of #systems solutions to supply the required #technologies and products for our customers.

Please help us understand what services would be of interest to you to  support your systems requirements, by getting in touch; we look forward to hearing from you.

Business Services
Day Rate Operations & Maintenance Engineering Site Visits Hardware Repair
Project Based Training Solutions Sourcing Software Support
Consultancy Telephone Assistance Spares Supply Reverse Logistics & Value Recovery

 

Enterprise Infrastructure
Alcatel-Lucent Bosch Ernitec Ganz
Huawei IBM Keymile Marconi
Nokia Pelco RAD 360Vision

 

Sustainable Solutions
Legacy Systems Refurbishment Testing Craft Terminals
Spares Sourcing Repairs Maintenance Technical Support
New Telecoms Infrastructure Functional Replacements Reverse Engineering Management Systems

 

Technologies & Products
PDH Access SDH Transport IP / MPLS CCTV Cameras
Copper Cabling Microwave Radio Pseudo-wire Solar Energy
IT / Servers DWDM / CWDM Carrier Ethernet PMR / TETRA