pecialist Complete Security Systems Ltd are an SSAIB recognized company that specializes in the design, installation and on-going maintenance of electronic security systems. Installer and maintainer of electronic security systems, including CCTV, Access Control, and Intruder detection.
There’s growing noise around smart homes and smarter security. You’ve probably heard it. But there is a place where access control and more have been smart for decades: the workplace. Home automation and IoT are still playing catch-up with the commercial sector. A new insights report from ASSA ABLOY and IFSEC Global — “The Smart Door Locks Report 2018” — measures just how fast consumer smart technology is running.
to a survey conducted for the report, 61% of households now claim to own at
least one smart home device or system. Energy monitors, home CCTV cameras,
intruder alarms and smart door locks are the most popular, according to the
report. All these functions, of course, have been available to businesses for
Educating The Smart Home Consumer
report data also questions how much consumers really know about their smarter
home. A surprising 42% of those surveyed, for example, were unaware they could
control a smart door lock from their phone. In fact, many leading smart door
lock models offer this feature, delivered by Wi-Fi or Bluetooth and an app.
Despite a wealth of features offered by the latest smart door locks — remote and location-based locking/unlocking; voice activation; timed access; emailed entry alerts; and integration with smart camera and lighting systems — most people still have limited knowledge of their capabilities.
Only 14% of survey respondents described themselves as “very familiar” with what a smart lock can do. Even though most of them probably use smart access control solutions at their workplace.
Secure Homes Through Smart Technology
and security are not the only drivers for smart home adoption. We humans also
love convenience, and modern living presents us with problems that smart home
technology can solve. Ironically, given the report’s findings, it takes a
smartphone to really unlock the convenient possibilities of smarter living. The
device that’s “always to hand” is central to the newest generation of
smart door locks. A smart door lock is a convenient way for a landlord or
agency to offer round-the-clock check-in and check-out
homeowners wish to remotely manage property access for friends and family, many
smart door locks oblige. You let in guests remotely, send them a virtual
digital key, or provide a temporary or single-use PIN to unlock the door.
is just as easy to revoke a digital key, if you don’t want its owner to come
around anymore. This is a significant improvement over sharing physical keys —
or hiding one under the doormat. We cannot be totally sure where a metal key
ends up and have no way to track or cancel it once it’s “out in the wild”.
Commercial access control offers such functionality as standard, of
addition, smart door locks offer more than just stand-alone operation and
clever functions. In a domestic setting, magic happens when locks work in
harmony with a home automation system, connected by protocols
like Z-Wave, ZigBee or Wi-Fi.
“Smart” Security On The
The smartphone is becoming a remote control for managing a connected life beyond just home (and even workplace) security. According to Accenture, the parcel delivery services market will grow by $343 billion by 2020. Just like home security, convenience is a major driver of change.
Vacation Rentals And Smart Home Tech
ABLOY research published in 2017 forecasts continued growth in the European
vacation rentals sector (at 5.8% CAGR). Smart door locks are also making an
impact here, at both ends of the market: for service providers — agents and
homeowners — and for travellers.
smart door lock is a convenient way for a landlord or agency to offer
round-the-clock check-in and check-out, without creating extra work or staff
costs. Both Intersoft, in Croatia, and Hoomvip in Spain have built vacation
rentals management systems around an app and the ENTR® smart door lock. Agents
issue, revoke, track and manage virtual keys for all their guests, saving
everyone time and hassle.
these visitors the smartphone is already an essential travel accessory. It is a
boarding pass, a credit card, a travel guide, and a postcard home… why not a
door key, too? And if this key is backed by a trusted home security brand — and
a company with vast experience in the mature market for commercial “smart”
security — better still.
New research has found an increasing appetite for smart city measures that aim to tackle urbanisation problems, such as congestion and security issues, with almost a quarter (24%) of Brits even saying they would be happy to fund these solutions using part of their own tax contributions.
The study of 1,000 people, conducted by ATG Access, found that this willingness rises substantially when it comes to funding measures which improve transport infrastructure. More than half (57%) would be happy for their tax to go towards smart traffic lights, and 44% for smarter signs which give real-time traffic updates.
Nearly a quarter (24%) said they would also be willing to fund smart barriers that help with incident management.
Investment in the smart city concept looks set to grow, with global spending expected to hit $135 billion by 2021. However, uptake in the UK has thus far been relatively slow with cost often cited as an issue.
Despite the current lack of investment, there is a clear interest in the smart city concept. 74% of people interested in smart city measures believe they would help to improve day-to-day issues, such as congestion.
Conducted as part of ATG’s ‘Smart cities: Turning the dream into a reality’ report, the research outlines the urbanisation problems that could be solved through the adoption of specific smart city concepts, such as traffic, crime and emergency incident response. It explores consumer attitudes and perceptions towards smart cities, and ways to overcome current barriers to adoption in the UK.
Gavin Hepburn, managing director at ATG Access, commented:
As our cities become more and more congested, it’s becoming increasingly clear that our current urban infrastructure is no longer fit for purpose and smart cities are a clear step forward.
However, despite the obvious benefits of the concept, there are still some issues to be circumnavigated if the UK smart city is to make the transition from far-flung concept to reality – with funding uncertainaties and costs a key issue.
“But what is apparent from our research is that people clearly see the benefits of a smart city. The solutions are available and in the most part, proven and tested, so it is time we begin to look for ways to help fund and support these types of projects that facilitate a safer and smarter future for our British cities.
A company which specialises in smart homes has made arrangements with a biometrics finger company in Austria in order to integrate the wall-mounted finger scanner into the house system and maximise security. Biometrics – measurements of unique parts the human body such as fingerprints, irises and faces – are much more difficult to hack or guess than a 4-digit PIN, and much more difficult to steal than a smart-card/keycard.
“eKey and Crestron took up the challenge of making door entry more secure and convenient,”
said Michael Short, global residential marketing manager for Crestron.
“To deliver on that, we focused on one of the aspects that makes us unique as human beings – fingerprints. Now, in essence, your finger is the key to your Crestron smart home.”
Georg Schaffer, head of export, eKey Biometric Systems GmbH, concluded, “As a specialist in fingerprint technology and a proven vendor of outdoor rated fingerprint readers, we are very excited about our partnership with Crestron and the possibilities of this advanced integration. It’s like turning Crestron into a biometric access control system by itself, featuring simplified administration centrally via – for instance – a Crestron touch screen. By saving multiple fingerprints of individual users, different functions can be triggered. Whereas your right index finger will become your new key for unlocking your front door, your left index finger will trigger a silent alarm when used under duress.”
SCS provides enhanced security for residential, retail and commercial installations. For maximum peace of mind, we offer a biometrics access control system, which can be programmed to also demand a smart-card for access. Multi-factor authentication is always more secure, and this biometrics and smart-card combination is no exception, since now no-one can enter your premises with just a stolen smart-card.
Our software can fine-tune and regulate individuals’ access control options, from the very broad, e.g. all employees can go here and all guests cannot, right down to, for example, one particular person can enter this room between the hours of 11am to 3pm.
If you’d like to find out more about the range of solutions supplied by SCS, both in terms of hardware (smart card readers, biometric readers, turnstiles, etc.) and software (access rights management software solutions, etc.), just contact us. We’ll be more than happy to answer any queries you may have.
CCTV cameras are everywhere in the UK and are considered one of the most efficient tools in preventing crime. But only if they work.
In order for CCTV cameras to be beneficial, they need to be correctly installed and maintained. If you stroll through any city and look closely, you will notice cameras everywhere. This may make you feel safe. But how many of them are truly capable of providing you with security?
Correct CCTV installation is not only about where the camera is placed, but also about how it is placed there, how it is connected to the rest of your company’s security and data systems, how the pictures are archived and who has access to them.
In other words, your CCTV system needs to be seamlessly integrated with your other management and ITC systems. They need to work together as a well-oiled machine in order for you to get the best possible results.
Not only do these elements make the difference between footage that can catch a criminal and footage that shows nothing useful, but many of them constitute legal requirements that fall into your responsibility.
Faulty CCTV deployment can incur huge costs in fines and damages suits. Even more, if your system isn’t properly installed, you may not use the footage as evidence when you need it the most. Last, but not least, what good is a CCTV system if it’s not thief-proof? Proper installation ensures that your system is not easy to tamper with and render it useless.
In CSC’s twenty years of experience of CCTV systems installation in commercial buildings, we have come across – and learned from – many CCTV deployment mistakes. In today’s post, we are going to talk about the most dangerous ones – the basis of the most important lessons we have learned.
1. Ignoring Environmental Factors in Monitored Areas
Ignoring environmental factors in monitored areas is the most common mistake made in CCTV deployment. The most intuitive example is ambient light level: insufficient or radically unequal lighting can result in undecipherable footage.
Other factors that you need to consider are:
Humidity, dust and vibration, which can severely impact the lifetime of the CCTV cameras, their storage media and their cabling.
Electronic / Magnetic interference, which may require special provisioning for long-distance data cables.
Environmental factors should play a role when planning deployment, selecting equipment, and installing the system. Even indoors equipment is susceptible to bad lighting conditions or electrical interference, so you should not ignore these concerns simply because your company’s offices are in an air-conditioned, clean glass building.
We carefully plan each installation and factor in environmental conditions before making any decisions or drilling any holes.
2. Ignoring the Monitoring and Storage Areas
Most CCTV users are primarily concerned with what they are monitoring, so they focus primarily on the cameras.
If live monitoring is required, the operators have to work from a secure room, where access is strictly controlled and logged. This room needs to have an adequate size and lighting, and – since the equipment usually generates a lot of heat – adequate ventilation and temperature control. In fact, some businesses opt to do the live monitoring off-premises.
Even if live monitoring is not accessed, the recorded pictures need to be stored and archived in a secure location, as businesses are legally responsible for the security of their CCTV footage.
Make sure that your storage room is not affected by humidity and that it’s perfectly safe from extreme weather conditions.
3. Treating CCTV and IT Infrastructure Separately
Infrastructure convergence is no longer something that security professionals are debating. Even large enterprises, where physical security and IT have been separate functions virtually throughout the history of IT, are no longer talking about whether it makes sense to treat them together, but about how they can optimize this convergence.
Maintaining a separate network for CCTV equipment, installed separately from the rest of the office network, with separate maintenance procedures and servicing contracts is a significant management and financial burden. It reduces the flexibility of your security systems, while needlessly increasing infrastructure costs. Networking service providers have long recognized this tendency and have begun to offer integrated network design and cabling services.
4. Inadequate Data and Power Cabling
Although physical security and IT are no longer separate functions, they do have specific – and separate – requirements. CCTV cameras have special installation requirements that range from legal restrictions to specific provisions regarding power and data cabling.
Most indoors CCTV cameras today use Cat-5/6 cables for their data connections, just like desktop computers. Higher-speed cameras, or cameras used for outdoors deployment tend to use fibre optic cables, which can carry data at higher speeds and over longer distances. Due to their convenience and ease of installation, wireless cameras are becoming increasingly popular – but even these require power cabling (albeit, if the electrical installation is adequate, over much shorter distances).
However, each type of cable only works over a certain range of distances and has special connection and interoperation requirements – for example, you cannot plug an optical SFP or OFP connector to your office router.
Mistakes made when choosing equipment tend to be costly to repair – and mistakes made while installing the cabling tend to be difficult to troubleshoot.
This is why you should always work with professionals for all your cabling and CCTV deployment needs. It may look cheaper to have a friend who “knows cabling and is techy” do the installation for you. But in the long run, it will definitely cost you a lot more to fix mistakes.
5. No Balance between Security and Maintenance
Good quality CCTV cameras are designed to be sturdy and reliable. If they are properly installed, most cameras end up being replaced due to growing customer demands or technical obsolescence, not because they break.
However, like all security equipment, CCTV cameras do need regular inspection and maintenance. It can be tempting to place cameras in inaccessible locations and permanently seal cables into their enclosures. Indeed, no one will be able to tamper with the cable or the camera – but changing a damaged cable or replacing the camera will be equally difficult.
It is crucial to think about your long-term investment here. Make sure that easy access to cables is granted and that the maintenance and repair teams can intervene quickly when there is a problem to be solved.
6. Not Following Legislation and Police Recommendations
Not following legislation is the single most disastrous mistake you can make when it comes to CCTV cameras. Being recorded at work or in a public place is a problem that everyone takes seriously. Leaking or misusing recorded information can have disastrous consequences for the persons recorded, even when they are not caught doing anything illegal.
This is why the UK has a very strict legislation related to what you can record and under what conditions. The fundamental act which governs how you are allowed to use information from CCTV cameras is the Data Protection Act (DPA) In short, according to the Data Protection Act, if you are using CCTV cameras on your commercial property, you must:
Let everyone know that CCTVs are being used and why (usually by putting up a sign announcing that “you may be recorded”).
Keep images only as long as your business needs them.
Be able to provide images within 40 days to anyone who has been recorded and, if you are asked, to the authorities.
The DPO itself is augmented by a number of other regulatory documents, primarily the Freedom of Information Act (FOIA) and the Protection of Freedoms Act (POFA). These requirements are outlined in the Surveillance Camera Code of Practice, issued under the POFA. The ICO’s handy code of practice also includes a useful, more down-to-earth overview of your responsibilities.
The legislation in this field is very murky and probably best left to experts in matters of law. However, you should at least be aware of its scope, and you should ensure that any third-party you work with is aware of it as well.
7. Bad Storage and Archival Practices
Most CCTV footage is not used immediately after being recorded. At a minimum, many burglaries against commercial properties take place during the night, so it can be hours before someone retrieves the recording. In other cases, it may take days or even weeks before someone notices something wrong and decides to look at CCTV footage, or before an official request from the authorities is delivered.
Consequently, CCTV footage needs to be properly archived. The basic guideline is that your system should be able to store 31 days of good quality pictures; there is rarely any reason to reduce this period, but for some businesses it can make sense to extend it.
Good storage practices are not just about storage capacity though. You also need to keep in mind that:
All recordings must be retained in a secure environment with adequate access controls and logging.
The tokens used to access secured data (passwords, encryption keys etc.) should be kept secure, only by authorized operators, but must be available at all times. Footage that can no longer be accessed is of no use.
Footage should be archived and indexed so that the desired fragment (usually identified by date and time) is easy to locate.
Fortunately, the Home Office issues a leaflet with 19 simple guidelines to follow in order to ensure the quality and safe storage of your CCTV footage.
8. Skipping System Validation
The installation of CCTV systems is often time- and resource-constrained. Many operators are content to just turn everything on and make sure that every camera seems to be recording and producing footage.
This can be sufficient for simple installations, which only have one or two security cameras pointed at the doors. But for more complex installations, this level of validation is dangerous.
Have you ever noticed how “alien” CCTV footage seems – how everything looks warped, how the surroundings look remarkably static and narrow, and how various features are unexpectedly blurry, even though others are crystal-clear?
That is because CCTV cameras have optic parameters that are quite different from those of the human eye. Unfortunately, that makes it hard to verify parameters like coverage and image detail just by looking at a screen for ten seconds.
The Home Office’s CCTV operations manual instead recommends that a set of vital parameters be verified according to a documented test procedure, based on design specifications. These parameters cover features such as:
Image parameters: field of view, image detail, live and recorded quality.
Integration with any other security system components, such as alarms, access control and motion detection systems.
Storage time and quality.
Does all this seem too complex? We’re not going to lie – it can be. Especially if you want to make sure you the CCTV system monitoring your office building is always functioning properly and is not easy to tamper with.
It may be tempting to purchase the cheapest cameras on the market and have your “tech guy” install them, but this will in no way guarantee your safety.
CSC have more than 20 years of experience in flawless CCTV deployment in London and the surrounding areas. We can make sure that you will get the most out of your system with a minimal investment. Plus, we always ensure that your CCTV system is sturdy and future-proof.
Want to know more about how we can help you install a new CCTV system or upgrade your existing one? Get in touch with us and claim your no-cost, no-obligations site survey!
Since the dawn of time or at least as long as we can recall different generations of Wireless Local Area Network (WLAN) technology or simply, WiFi, has been known by its industry standard designations IEEE 802.11 dot something.
In the world of wireless, the term Wi-Fi is synonymous with wireless access in general, despite the fact that it is a specific trademark owned by the Wi-Fi Alliance, a group dedicated to certifying that Wi-Fi products meet the IEEE’s set of 802.11 wireless standards.
These standards, with names such as 802.11b (pronounced “Eight-O-Two-Eleven-Bee”, ignore the “dot”) and 802.11ac, comprise a family of specifications that started in the 1990s and continues to grow today. The 802.11 standards codify improvements that boost wireless throughput and range as well as the use of new frequencies as they become available. They also address new technologies that reduce power consumption.
You can now forget all these confusing alphabet soups of initials and 802.11 numbers because the Wi-Fi Alliance have adopted consumer friendly naming conventions.
The new naming system is said to identify Wi-Fi generations by a “numerical sequence which correspond to major advancements in Wi-Fi” (i.e. that’s a roundabout way of saying 1, 2, 3 etc.). For example, the very latest 802.11ax standard will now simply be called Wi-Fi 6, which is certainly simpler, but we dare say that most enthusiasts will merely shrug their shoulders and let out a muted sigh.
For nearly two decades, Wi-Fi users have had to sort through technical naming conventions to determine if their devices support the latest Wi-Fi. Wi-Fi Alliance is excited to introduce Wi-Fi 6, and present a new naming scheme to help industry and Wi-Fi users easily understand the Wi-Fi generation supported by their device or connection.
Edgar Figueroa, President and CEO of the Wi-Fi Alliance.
What is Wi-Fi 6? Wi-Fi 5? Wi-Fi 4?
The IEEE naming scheme for the standard is a little tough to get used to, and in an effort to make it easier to understand, the Wi-Fi Alliance has come up with some simpler names.
Under its naming convention, the alliance calls 802.11ax Wi-Fi 6. 802.11ac is now Wi-Fi 5, and 802.11n is Wi-Fi 4.
Meanwhile it’s important to know that the Wi-Fi Alliance has not made up simpler names for all the 802.11 standards, so it’s important to be familiar with the traditional designations. Also, the IEEE, which continues to work on newer versions of 802.11, has not adopted these new names, so trying to track down details about them using the new names will make the task more complicated.
The traditional names of these standards create quite an alphabet soup, made all-the-more confusing because they are not arranged alphabetically. To help clarify the situation, here’s an update on these physical-layer standards within 802.11, listed in reverse chronological order, with the newest standards at the top, and the oldest toward the bottom. After that is a description of standards that are still in the works.
Also known as Wi-Fi HaLow, 802.11ah defines operation of license-exempt networks in frequency bands below 1GHz (typically the 900 MHz band), excluding the TV White Space bands. In the U.S., this includes 908-928MHz, with varying frequencies in other countries. The purpose of 802.11ah is to create extended-range Wi-Fi networks that go beyond typical networks in the 2.4GHz and 5GHz space (remember, lower frequency means longer range), with data speeds up to 347Mbps. In addition, the standard aims to have lower energy consumption, useful for Internet of Things devices to communicate across long ranges without using a lot of energy. But it also could compete with Bluetooth technologies in the home due to its lower energy needs. The protocol was approved in September 2016 and published in May 2017.
Approved in December 2012, 802.11ad is very fast – it can provide up to 6.7Gbps of data rate across the 60 GHz frequency, but that comes at a cost of distance – you achieve this only if your client device is situated within 3.3 meters of the access point.
802.11ac (Wi-Fi 5)
Current home wireless routers are likely 802.1ac-compliant and operate in the 5 GHz frequency space. With Multiple Input, Multiple Output (MIMO) – multiple antennas on sending and receiving devices to reduce error and boost speed – this standard supports data rates up to 3.46Gbps. Some router vendors include technologies that support the 2.4GHz frequency via 802.11n, providing support for older client devices that may have 802.11b/g/n radios, but also providing additional bandwidth for improved data rates.
802.11n (Wi-Fi 4)
The first standard to specify MIMO, 802.11n was approved in October 2009 and allows for usage in two frequencies – 2.4GHz and 5GHz, with speeds up to 600Mbps. When you hear wireless LAN vendors use the term “dual-band”, it refers to being able to deliver data across these two frequencies.
Approved in June 2003, 802.11g was the successor to 802.11b, able to achieve up to 54Mbps rates in the 2.4GHz band, matching 802.11a speed but within the lower frequency range.
The first “letter” following the June 1997 approval of the 802.11 standard, this one provided for operation in the 5GHz frequency, with data rates up to 54Mbps. Counterintuitively, 802.11a came out later than 802.11b, causing some confusion in the marketplace because consumers expected that the standard with the “b” at the end would be backward compatible with the one with the “a” at the end.
Released in September 1999, it’s most likely that your first home router was 802.11b, which operates in the 2.4GHz frequency and provides a data rate up to 11 Mbps. Interestingly, 802.11a products hit the market before 802.11a, which was approved at the same time but didn’t hit the market until later.
Pending Wi-Fi standards
802.11ax (Wi-Fi 6)
Known as High Efficiency WLAN, 802.11ax aims to improve the performance in WLAN deployments in dense scenarios, such as sports stadiums and airports, while still operating in the 2.4GHz and 5GHz spectrum. The group is targeting at least a 4X improvement in throughput compared to 802.11n and 802.11ac., through more-efficient spectrum utilisation. Approval is estimated to be in July 2019.
Also known as Next Generation 60GHz, the goal of this standard is to support a maximum throughput of at least 20Gbps within the 60GHz frequency (802.11ad currently achieves up to 7Gbps), as well as increase the range and reliability. The standard is expected to be approved between September and November 2019.
Called Next Generation Positioning (NGP), a study group was formed in January 2015 to address the needs of a “Station to identify its absolute and relative position to another station or stations it’s either associated or un-associated with.” The goals of the group would be to define modifications to the MAC and PHY layers that enable “determination of absolute and relative position with better accuracy with respect to the Fine Timing Measurement (MTM) protocol executing on the same PHY-type, while reducing existing wireless medium use and power consumption, and is scalable to dense deployments.” The current estimate on approval of this standard is March 2021.
Otherwise known as “Wake-Up Radio” (WUR), a new technology aimed at extending the battery life of devices and sensors within an Internet of Things network. The goal of the WUR is to “greatly reduce the need for frequent recharging and replacement of batteries while still maintaining optimum device performance.” This is currently expected to be approved in July 2020.
WI-Fi Take Away:
Expect to see the first fully certifiedWi-Fi 6 commercial kit hit store shelves later this year. Theoretical peak data speeds of up to 10Gbps are being promised over the combined 2.4GHz and 5GHz radio spectrum bands, alongside better management of spectrum in congested environments. Until then continue to deploy 802.11ac or Wi-Fi 5 equipment.
Wi-Fi 6 (802.11ax) – Expected the standard to be published in early 2019, this version will improve on the coordination of data transmitting between the router and several devices wirelessly connected to it. It’s meant to accommodate the growing use of internet-connected devices (AI assistants, cameras, lights, speakers, thermostats, etc.). The main way it increases speed is by fully combining the 2.4GHz and 5GHz spectrum bands. Previously, 802.11ac and 802.11n (or Wi-Fi 4) were forced to work on the two bands separately, but the new standard will utilise them simultaneously. MU-MIMO technology will also be enabled for uplink data, in addition to the downlink data it already supports.
Wi-Fi 5 (802.11ac) – Published in December 2013, this is the version that’s found in the latest, top-of-the-line routers and devices you can buy today. It was designed to meet the growing need for moving large amounts of data throughout a Wi-Fi network, such as for cloud storage services and streaming high-resolution video. Its top speed is 3.4 Gbps.
Wi-Fi 4 (802.11n) –Published in October 2009, this version tops 600 Mbps and nearly doubles the broadcast range of its predecessors. It uses multiple antennas to hit such high speeds.
Global Access Control Market was valued at USD 6.8 billion in 2017, and is expected to reach a value of USD 11.1 billion by 2023 at a CAGR of 8.45%, over the forecast period (2018-2023).
According to the FBI’s Internet Crime Complaint Center (IC3), the Business Email Compromise (BEC) scam saw an increase of 1,300% in identified exposed losses, totaling over USD 3 billion, since January 2015. Such losses could be better controlled through the use of access control software. According to the Association of Fraud Examiners in 2015 the amount of internal theft accounts for about 5% of annual revenue for companies.
The implementation of access control systems contributes to the growth in the safety and security of office surroundings. Such identity theft of data has been increasing owing to which governments have been adopting the use of access control systems. As the cyber attacks, frauds and government authentication mandates continue to grow in sophistication and scope, the need to strengthen security while reducing costs is paramount across various industry verticals.
The implementation of access control systems contributes to the growth in the safety and security of office surroundings. Such identity theft of data has been increasing owing to which governments have been adopting the use of access control systems.
As the cyber-attacks, frauds and government authentication mandates continue to grow in sophistication and scope, the need to strengthen security while reducing costs is paramount across various industry verticals.
To lear more about how SCS can help with Access Control please contact us.