70-333 Exam Guide: Deploying Enterprise Voice with Skype for Business 2015
Exam 70-333, identified by Microsoft as “Deploying Enterprise Voice with Skype for Business 2015,” validates practical knowledge of planning, deploying, configuring, and administering Enterprise Voice in an on-premises Skype for Business Server environment. It is most relevant to administrators and communications engineers working with PSTN connectivity, Mediation Servers, trunks, dial plans, voice policies, and user enablement. The key decision for a candidate today is whether the exam is still an attainable credential objective or whether its technical scope should instead guide preparation for a current role-based path. This guide helps you make that decision and study the underlying skills efficiently.
What does 70-333 cover?
70-333 focuses on deploying Enterprise Voice with Skype for Business 2015 rather than on general Skype for Business administration alone. Microsoft’s documentation places the product across planning, installation, deployment, configuration, management, and Enterprise Voice topics, while the Enterprise Voice material concentrates on connecting users to telephone services and operating the supporting voice infrastructure.
The practical subject is a complete voice deployment: deciding where voice services belong in the topology, selecting PSTN connectivity, preparing security and administration, configuring routing objects, enabling users, and adding advanced call-management capabilities. A candidate should therefore study relationships between components and deployment decisions, not isolated definitions.
The credential context matters before you study
Microsoft identified 70-333 as one of the exams associated with the older MCSA, MCSD, and MCSE certification system. Microsoft’s retirement announcement said those remaining exams were scheduled to retire during the move toward role-based certifications. The announcement contains retirement information from 2020 and an updated statement referring to January 31, 2021, so candidates should confirm any current availability directly through Microsoft before planning a booking.
If the exam is unavailable, do not treat an unofficial practice-test catalogue as evidence that a booking can be made. The technical subjects remain useful for legacy Skype for Business Server work, migration planning, and troubleshooting, but the credential decision and the skills decision are separate. Verify the current Microsoft certification or transcript position first, then decide whether to pursue the legacy exam or use its scope as a study outline.
Who should use this guide?
This guide suits administrators responsible for on-premises Skype for Business voice, engineers integrating a deployment with a PSTN gateway or SIP trunk, and candidates who need to understand how planning choices affect routing, resilience, and user calling. It is less suitable as a first exposure to networking, certificates, Windows administration, or unified communications concepts.
A strong candidate does not need to memorize every page in the product documentation. The candidate does need to explain why a Mediation Server is placed in a particular way, how a call reaches the PSTN, which policy controls a user’s calling behavior, and what must be normalized before routing can work.
Which skills should you measure?
No percentage-based 70-333 blueprint is supplied in the official research for this guide, so this article does not assign invented domain weights. Measure readiness through the documented work sequence instead: plan the topology, prepare prerequisites, deploy voice components, configure call routing, enable users, and validate feature and resilience choices.
Use the following capability areas as a practical assessment model. They are derived from Microsoft’s Enterprise Voice planning and deployment documentation, not presented as an official exam weighting. A candidate who can perform or clearly explain each area is preparing against the actual technical work described by Microsoft.
Plan sites, regions, links, and capacity
Planning begins with the sites where Enterprise Voice will operate, the network regions containing those sites, the links between central and branch locations, expected call volume, redundancy, failover, and existing PBX equipment. PSTN connectivity is also a site decision: gateways may be local, Survivable Branch Appliances may be appropriate, or SIP trunks may terminate locally or at a central site.
Capacity reasoning must use the traffic assumptions explicitly and carefully. For Light traffic, defined as one PSTN call per user per hour, Microsoft says to figure 15 users per port. For Medium traffic, defined as 2 PSTN calls per user per hour, Microsoft says to figure 10 users per port. For Heavy traffic, defined as 3 or more PSTN per user calls per hour, Microsoft says to figure 5 users per port. Treat these as planning metrics, not as a substitute for a complete traffic and resilience assessment.
A useful exercise is to take a fictional multi-site organization and write down the sites, regions, WAN characteristics, local PSTN requirements, and failure behavior. Then justify the choice of local gateway, central connectivity, branch survivability, or call admission control. The goal is to connect a topology choice to a stated operational constraint.
Recognize the Enterprise Voice components
Microsoft identifies Mediation Servers, PSTN connectivity components, Edge Servers, and Front End Server voice components as parts of an Enterprise Voice topology. A Mediation Server translates signaling and, in some configurations, media between Skype for Business Server, the Enterprise Voice infrastructure, and a PSTN gateway or SIP trunk. It may be collocated with Front End Servers or installed as a standalone server or pool.
PSTN connectivity may use a gateway or SIP trunk. Edge Servers support Enterprise Voice use outside the organization’s firewall: Access Edge provides SIP signaling, while A/V Edge supports media traversal of network address translation and firewalls. The A/V Authentication service provides authentication for the A/V Edge service.
Study the components as a call path. Ask what happens when an internal user calls an external number, which component translates signaling, where the PSTN boundary exists, and what changes when the user is outside the corporate firewall. This method is more useful than memorizing a component list without understanding its role.
Prepare security and administrative prerequisites
Before deployment, Microsoft says deployment administrators should belong to the RTCUniversalServerAdmins group. Voice configuration work can be performed through the CsVoiceAdministrator role, user management through the CsUserAdministrator role, and the CsAdministrator role can perform the tasks of both. A managed key infrastructure must also be deployed and configured through a Microsoft or third-party certification authority infrastructure.
The preparation decision is to separate infrastructure readiness from voice configuration rights. An administrator may have enough access to enable users but not enough authority to perform every voice configuration task. Likewise, a topology can be logically correct but still fail operationally if certificates or administrative roles are not ready.
Create a prerequisite checklist with two columns: required infrastructure and required authority. Include certificate planning, administrator group or role membership, user data, and PSTN connectivity information. Do not assume that an account’s ability to open a console proves that it has every required permission.
Configure the deployment sequence
Microsoft’s central-site deployment guidance presents a sequence that includes prerequisites, Mediation Server deployment, gateway and trunk definition, trunk configuration, caller ID and called ID translation rules, normalization rules, dial plans, voice policies, PSTN usage records, voice routes, user enablement, and advanced Enterprise Voice features. The sequence reflects dependencies: routing objects are difficult to validate until connectivity and numbering assumptions are clear.
The documentation distinguishes collocated and standalone Mediation Server arrangements. When Mediation Server is collocated with each Front End Server or Standard Edition server and the topology was defined and published accordingly, the deployment process may already have installed the relevant files. A standalone Mediation Server pool requires its own planning and installation path.
Build a study diagram that starts at topology design and ends at a user placing a call. Annotate every transition with the object or service involved. Then reverse the diagram for troubleshooting: begin with a failed call and identify whether the likely issue is user enablement, policy assignment, number normalization, route selection, trunk configuration, gateway reachability, or media traversal.
Enable users and assign the right policies
Enabling a user is not complete merely because Enterprise Voice is selected. Microsoft requires a unique, normalized primary phone number in the user’s Line URI property. The user must also receive a voice policy and a dial plan, whether those are inherited globally, applied at the site level, or assigned specifically to the user.
The documented user workflow includes enabling the account for Enterprise Voice, optionally assigning a user-specific voice policy, and optionally assigning a user-specific dial plan. Global and site-level policies can apply automatically, while per-user policies require explicit assignment. Microsoft’s guidance identifies Skype for Business Server Control Panel for the initial user enablement procedure and Management Shell cmdlets for the remaining assignment procedures.
Practice distinguishing the default policy path from an explicit override. For each sample user, record the home site, Line URI, effective voice policy, effective dial plan, and intended PSTN access. This prevents a common preparation error: knowing the command or menu action but not knowing which effective setting the user actually receives.
Understand advanced and limited voice options
Enterprise Voice is the fuller on-premises voice option and supports capabilities such as Response Groups, Call Park, team calling, Group Call Pickup, and Enhanced Emergency E9-1-1. Call Via Work integrates Skype for Business with an existing PBX and uses the user’s PBX phone for calls. Microsoft describes Call Via Work as having a more limited feature set, including no support for delegation, team call, response group, or Enhanced E9-1-1.
Remote call control belongs to an earlier Lync Server scenario. Microsoft states that it is not supported for users homed on Skype for Business Server servers, although it is supported for Skype for Business clients still homed on Lync Server 2013. Keep these scenarios separate when studying: a familiar feature from an earlier platform is not automatically a supported Skype for Business Server deployment choice.
For each advanced feature, write three notes: the user experience it provides, the infrastructure or policy dependency it introduces, and whether it belongs to Enterprise Voice, Call Via Work, or a previous Lync scenario. This classification exercise is a better defense against distractors than memorizing feature names alone.
How should you prepare without relying on dumps?
Use the official documentation as a build-and-reason curriculum, then test yourself with scenarios you create from the documented objects and decisions. Dumps and leaked-question claims are not a reliable substitute for understanding, and memorizing answer patterns cannot guarantee a pass. Your preparation should show that you can select and justify a configuration under changing site, network, numbering, and user requirements.
Read in dependency order
Start with the Skype for Business Server 2015 documentation overview so you can place Enterprise Voice within the wider product lifecycle. Move next to the Enterprise Voice solution planning pages, then the required-components page, then security prerequisites, deployment procedures, and user enablement. This order moves from architecture to implementation and reduces the risk of learning commands without understanding their prerequisites.
Do not read every topic at the same speed. Read planning material for decision logic, deployment material for order and dependencies, security material for permissions and certificates, and user-enablement material for effective configuration. Capture terms in a table with columns for purpose, dependency, scope, and failure symptom.
Build a small lab or paper deployment
A real lab is useful when it is available, but the official research does not establish a particular lab topology, delivery method, or test environment. If you cannot build one, create a paper deployment that includes a central site, a branch site, WAN characteristics, a PSTN gateway or SIP trunk, users, and a numbering plan.
For every design choice, record the constraint that caused it. For example, ask whether a constrained WAN requires call admission control, whether a branch requires local survivability, whether a gateway should be local, and whether a user needs a site-level or per-user policy. This produces transferable reasoning rather than a collection of screenshots.
Practice configuration objects as a chain
Study trunks, translation rules, normalization rules, dial plans, PSTN usage records, voice policies, and voice routes as a connected routing system. A number may be valid for a user but still fail to reach the intended destination if normalization, policy, usage, route, or trunk assumptions do not align.
Use a written call trace for internal-to-PSTN, PSTN-to-user, and branch-to-central scenarios. Mark the input number, normalized form, applicable dial plan, voice policy, PSTN usage, selected route, trunk or gateway, and expected failure point. Do not invent undocumented behavior; use the exercise to identify which official topic must be checked when a decision depends on a detail not established in your notes.
Use retrieval questions instead of passive rereading
After each study session, close the documentation and answer questions such as: Why is a Mediation Server needed? What is the difference between a SIP trunk and a PSTN gateway in the topology? Which Edge service supports signaling and which supports media traversal? What makes a Line URI acceptable? When does a global policy apply automatically?
Then verify every answer against Microsoft Learn. Mark answers as confirmed, partly understood, or unresolved. The unresolved list should drive the next session. This feedback loop is more efficient than repeatedly rereading familiar pages and gives you an auditable record of what still requires work.
What mistakes waste the most study time?
Most avoidable errors come from collapsing separate layers into one. Candidates often treat a phone number, a dial plan, a voice policy, and a route as interchangeable; assume a gateway alone completes the deployment; or overlook certificate and role prerequisites. Correct those conceptual gaps before spending more time on low-level detail.
Mistake: treating a normalized number as the whole configuration
A normalized Line URI identifies the user’s primary phone number, but Microsoft also requires an applicable voice policy and dial plan. A candidate who remembers only the phone-number format may miss the policy inheritance and assignment model that determines how calls are handled.
Fix this by writing an effective-configuration summary for every practice user. Include the Line URI, policy source, dial-plan source, site, and intended calling scope. If one field is inherited, state where it comes from rather than leaving it blank.
Mistake: memorizing component names without call flow
Listing Mediation Server, gateway, SIP trunk, and Edge Server is not enough. The important distinction is what each component contributes. Mediation Servers translate signaling and sometimes media; PSTN connectivity components connect the deployment to telephone networks; Edge services support external-user signaling, media traversal, and authentication.
Fix this with a call-path sketch for each scenario. Add a note explaining why the component is present and what would be affected if it were unavailable. The sketch should also distinguish internal deployment traffic from traffic crossing the organization’s firewall.
Mistake: ignoring branch conditions
A branch design cannot be selected from user count alone. Microsoft’s planning guidance also considers WAN resilience, available bandwidth, local trained administrators, local PSTN needs, and survivability. Branch choices therefore require matching several facts to one recommendation.
Fix this by making scenario cards that vary one condition at a time. Change WAN resilience, bandwidth, local administration, or branch population and reconsider the design. Keep Microsoft’s documented thresholds and recommendations attached to their exact conditions; do not generalize them into universal rules.
Mistake: confusing Enterprise Voice with Call Via Work
Both options integrate telephony with Skype for Business, but they are not equivalent. Enterprise Voice is the fuller VoIP solution, while Call Via Work uses the existing PBX phone and omits several Enterprise Voice features. Treating them as interchangeable leads to incorrect feature and migration decisions.
Fix this by creating a two-column comparison based only on documented capabilities. Add a third column for transitional scenarios, such as users retaining PBX phones while adopting Skype for Business calling workflows.
Mistake: studying retired-exam claims as current booking advice
A page offering 70-333 materials does not establish that Microsoft currently schedules the exam. The official retirement announcement concerns historical retirement dates and legacy certification paths. Candidates should verify current availability, transcript treatment, and any alternative certification through Microsoft rather than relying on catalogue labels or third-party claims.
Fix this before investing in a long study plan. If the exam is not available, retain the technical roadmap for job preparation and redirect certification planning toward a current Microsoft role-based option that matches the intended work.
What is a practical study roadmap?
A staged roadmap keeps planning, deployment, and administration connected. Begin with architecture and decision conditions, move through prerequisites and deployment order, then finish with routing, user enablement, resilience, and scenario review. Adjust the pace to your background; the sequence is a recommendation, not an official Microsoft duration or schedule.
Stage 1: establish the platform frame
Read the Skype for Business Server 2015 documentation landing page and map its planning, installation, deployment, configuration, management, and Enterprise Voice sections. Write a one-page explanation of where Enterprise Voice fits and what kinds of work are outside its immediate scope.
Your checkpoint is the ability to explain the product context without drifting into unsupported exam claims. If you cannot describe the difference between a general server deployment topic and an Enterprise Voice deployment topic, remain in this stage before studying routing details.
Stage 2: make topology decisions
Study sites, regions, WAN links, PSTN connectivity, redundancy, failover, existing PBX equipment, branch survivability, and traffic estimation. Build two or more paper designs with different network conditions. Attach each choice to the documented reason for it.
Your checkpoint is a defensible topology narrative. It should identify where gateways, SIP trunks, Mediation Servers, and branch components belong, how outside users connect, and which assumptions still need validation in the official documentation or in the organization’s design records.
Stage 3: prepare security and components
Review administrative groups and roles, managed key infrastructure, certificates, user phone-number preparation, Mediation Server placement, PSTN connectivity, and Edge requirements. Create a prerequisite gate: do not proceed to routing until the gate identifies the required authority, certificate infrastructure, and connectivity components.
Your checkpoint is a deployment-readiness review. Explain what can be configured by a voice administrator, what user-management authority is needed, and why a deployment can be blocked before any dial plan or route is created.
Stage 4: trace deployment and routing
Follow the documented central-site sequence from Mediation Server and gateway definition through trunks, translation and normalization rules, dial plans, voice policies, PSTN usage records, voice routes, and advanced features. Draw a call flow after each topic and update it when a new dependency appears.
Your checkpoint is a complete configuration chain. Given a stated user, number, policy, and PSTN destination, you should be able to identify the configuration objects that must align and the documentation topic to consult when an object’s exact behavior is uncertain.
Stage 5: enable users and test scenarios
Practice the difference between account enablement, Line URI assignment, inherited policies, site-level policies, and explicit per-user assignments. Create scenarios for a new user, a user at a site with site policies, and a user requiring a specific policy or dial plan. Validate each scenario against the user-enablement guidance.
Your checkpoint is an effective-settings explanation, not merely a sequence of clicks. State which setting is assigned, where it is inherited from, and what administrative role or Management Shell action the documented procedure requires.
Stage 6: perform a final evidence review
Review only the areas where your scenario answers were weak: branch resilience, PSTN capacity, certificates, Edge services, routing objects, Call Via Work limitations, or user policy inheritance. Reopen the official page for each weak area and rewrite the answer in your own words.
Before scheduling anything, verify the current status of 70-333 through Microsoft. If the exam is unavailable, stop treating a booking as the next action. Use the same review to select a current role-based certification or a job-specific learning plan, depending on your objective.
How can you judge readiness honestly?
Readiness means you can reason from requirements to configuration and explain the consequence of a wrong choice. It does not mean you have memorized a question bank. Use scenario performance, documentation verification, and clear explanations as your final checks, especially because the supplied research does not include an official question count, duration, passing score, delivery method, languages, or current registration details.
Use a scenario-based self-check
Choose a deployment with several sites, a mixture of resilient and constrained links, an existing PBX, external users, and different user calling requirements. Without notes, identify the planning facts you need, the required components, the prerequisite permissions and certificates, the routing objects, and the user settings.
Then inspect your answer for unsupported assumptions. A strong response states what is known from Microsoft’s guidance, what is an organization-specific design decision, and what must be verified elsewhere. This distinction is important in both examination preparation and production planning.
Explain why an answer is right
For each selected design, give a short reason tied to a documented condition. For example, explain why local PSTN connectivity is preferred in one site design, why call admission control may matter on a constrained link, or why a user-specific policy is unnecessary when the correct site-level policy already applies.
If you can select an option but cannot explain it, mark the topic as weak. Explanation exposes accidental memorization and makes it easier to transfer knowledge to a differently worded scenario.
Check the source before trusting a detail
Use Microsoft Learn for claims about product behavior, prerequisites, components, deployment order, and historical certification status. The supplied official pages provide no verified exam blueprint percentages, exam duration, question count, price, language list, or current delivery information, so do not fill those gaps with estimates or third-party assertions.
Keep a source log with the page title, the decision it supports, and the date you reviewed it. For a retired or legacy exam, revisit the certification page before making a scheduling or purchasing decision because availability and credential pathways are time-sensitive.
What should you do next?
First confirm whether Microsoft currently offers 70-333 for registration. If it is unavailable, preserve the technical study value but change the objective from booking a legacy exam to building demonstrable Skype for Business voice capability or choosing a current role-based certification. If it is available in the channel you intend to use, use Microsoft’s current registration information rather than relying on this technical guide for logistics.
Next, create a study inventory with six headings: topology planning, Enterprise Voice components, security prerequisites, deployment sequence, routing and policies, and user enablement. Under each heading, list one scenario you can solve and one source page you must be able to navigate. Study the weakest heading first, then repeat the scenario check.
Finally, avoid dumps that claim to reproduce live questions or promise a pass through memorization. Use official documentation, controlled practice, and written design reasoning. That approach prepares you for the actual work behind 70-333 and remains useful even when the historical certification route is no longer the appropriate next step.
Sources and scope note
This guide uses only the supplied Microsoft Learn research. Technical descriptions are grounded in Microsoft’s Skype for Business Server 2015 and Enterprise Voice documentation. Statements about exam identity and retirement are based on Microsoft’s historical certification announcement. No official 70-333 blueprint percentages or current exam-delivery details were supplied, so none are presented as facts.
Conclusion
Treat 70-333 as a decision point, not simply a list of study topics. Verify its current status before planning a booking, then use the documented Enterprise Voice workflow to assess your skills: plan the sites and links, identify components, satisfy security prerequisites, deploy connectivity, configure routing, and enable users with the correct effective policies. If the legacy exam is unavailable, that same workflow still provides a focused foundation for maintaining Skype for Business Server environments and selecting a more current certification path.
