On this page
- 01Before you start
- 02Where it sits in the project
- 03Access control versus Time & Attendance
- 04System types and architecture
- 05Readers and credential technologies
- 06Controllers, communication and door capacity
- 07Electronic locks, monitoring and life safety
- 08Access levels, schedules and security rules
- 09Time & Attendance in detail
- 10Integration
- 11Design workflow and BoQ essentials
- 12Recommended priorities by application
- 13Check that it works
- 14Common problems and how to fix them
- 15Frequently asked questions
- 16Talk to PSS about access control
An Electronic Access Control System (EACS) verifies a person’s credential, evaluates the applicable permissions, and decides whether a controlled entry point should unlock. It answers two questions at every door: who is allowed through, and who actually went through. The first is a policy enforced by a controller; the second is an event log that must stand up in an investigation.
The reader on the wall is only the interface. The lock and its power supply decide whether the door is safe; the quality of the data decides whether the system is worth owning. A project priced as “readers and cards” misses the two items behind most failures: door hardware selection and life-safety release. Both are settled long before the first card is encoded.
Physical access control and Time & Attendance (T&A) are related but distinct. Access control focuses on controlling and recording entry and exit. Time & Attendance focuses on working hours, lateness, overtime and absence. A single biometric terminal may support both functions, but the software logic, hardware architecture and reporting can differ substantially. Confirm the required outcome before recommending the hardware.
| Function | Purpose |
|---|---|
| Identification | Establishes which user is requesting access |
| Authentication | Verifies the presented credential or identity |
| Authorization | Determines whether that user may enter that area at that time |
| Door control | Releases or maintains the lock according to the rules |
| Monitoring | Tracks door status, forced-door and door-held-open conditions |
| Audit trail | Records access attempts and relevant security events |
| Alarm management | Generates alerts for defined security conditions |
Before you start
- Door schedule with direction of travel and user groups; which doors are escape routes and what the fire strategy demands.
- Who provides the fire-alarm relay — and is it monitored? BS 7273-4 category?
- Access control only, T&A only, or both — and can they be processed separately?
- Card technology (DESFire?), reuse of existing cards, mobile credentials, multi-factor for restricted areas.
- Controllers: door/reader capacity, OSDP, offline buffering, network, UPS, placement.
- Lock type per door; local PSU sizing; REX and break-glass.
- HR attendance rules, biometrics legal basis, payroll export format.
- Integrations: CCTV, intrusion, fire, BMS — scoped with acceptance criteria.
- Maintenance: who opens a door at two in the morning?
Where it sits in the project
Access control sits between three trades: the door supplier (frames and preparation), electrical (power, fire alarm interface, containment), and IT (network, time source, user accounts). It also touches HR for attendance and civil defence for egress. The expensive mistakes happen early: an electric strike must be specified before the frame is fabricated, and a maglock needs a door leaf that can carry its weight and armature plate.
Access control versus Time & Attendance
| Feature | Access Control | Time & Attendance |
|---|---|---|
| Primary objective | Physical security | Workforce time management |
| Main question | Is this person allowed to enter? | When did this employee work? |
| Typical hardware | Readers, controllers, locks, sensors | Biometric / card terminals, mobile clocking |
| Main software | Access rights, door schedules, alarms, event logs | Shifts, lateness, overtime, payroll reports |
| Door locking / anti-passback | Core functions | Not normally required |
| Payroll / HR integration | Optional or indirect | Common requirement |
An employee may be permitted to enter at 7:00 AM while the attendance policy starts work at 8:00 AM — two different purposes. Device capability does not mean the complete system supports both functions properly. Before selecting a combined terminal, verify: relay outputs and door interfaces; door sensors, exit buttons and lock monitoring; attendance rules, shift calculations and exception reporting; separate processing of access and attendance events; capacity and communication interfaces; payroll/HR compatibility.
A standalone attendance terminal may be fine for HR and inadequate for a server room. A sophisticated door system may log entry without providing the shift calculations payroll needs.
System types and architecture
Standalone — reader/terminal controls a door without a permanent central server. Simple for a few doors; limited centralized administration and reporting.
Network-based — controllers and readers managed centrally over IP. Scalable multi-door logs, reporting and integration with CCTV, intrusion and visitor systems.
Distributed / intelligent controllers — local decisions, credential storage, schedules and event buffers; doors can continue during temporary server or network outage. Verify offline capacity, update behaviour during outage, resynchronisation, power backup and recovery.
Cloud-managed — remote administration and multi-site convenience; check internet dependency, licensing, privacy, cybersecurity, offline behaviour and hardware compatibility. Cloud-managed does not mean every door transaction needs the cloud.
Hybrid — useful when upgrading without replacing all field equipment; verify interface, firmware, protocol, credential and software compatibility. A shared connector type is not automatic feature compatibility.
Typical components and transaction flow
Management software → server/appliance (where required) → panel/controller → reader or biometric terminal → electronic lock → door contact → REX → emergency release → power supply and battery/UPS → network.
- User presents a credential.
- Reader/terminal sends data to the controller (or decides locally).
- System checks authorization data and rules.
- If permitted, the lock output activates for the configured period.
- User opens the door; the contact reports state if installed.
- System logs the event and may alert on forced-open or held-open.
Readers and credential technologies
| Technology | Security level | Practical note |
|---|---|---|
| 125 kHz proximity | Low | Trivially cloned; unsupervised internal doors only |
| MIFARE Classic | Low | Cryptography broken; do not specify in new projects |
| DESFire EV2/EV3 | High | AES with mutual authentication; default for new work |
| PIN keypad | Depends on policy | Observation and sharing risks; often a second factor |
| Fingerprint / face / iris / palm-vein | High (when well designed) | Personal data — legal basis, encrypted storage, liveness where risk demands |
| Mobile credential | High when properly provisioned | BLE/NFC; verify compatibility, revocation, offline behaviour, licensing |
| Card + PIN (or biometric) | Stronger multi-factor | Restricted areas; do not over-apply to every low-risk door |
Operating frequency alone does not establish security — two 13.56 MHz cards can differ completely. Confirm card technology, authentication, format, encryption and reader/controller compatibility. Environment: IP65–IP67 outdoors (IEC 60529), IK08–IK10 impact (IEC 62262).
Controllers, communication and door capacity
Controllers typically support one, two, four or more doors. Selection criteria: door and reader count, interfaces, I/O capacity, credential and event buffers, offline operation, network protocols, encryption, expansion and software fit. Lowest controller count is not always best — consider cable distances, secure placement, outage impact, enclosure capacity, power and expansion.
Prefer controllers in secure service locations, not public areas. For higher security: tamper monitoring, secure communications, supervised inputs, protected enclosures and offline continuation.
Wiegand versus OSDP
| Feature | Wiegand | OSDP |
|---|---|---|
| Direction | Primarily reader → controller | Bidirectional |
| Supervision | Limited | Supported |
| Secure Channel | Not a standard capability | Supported when enabled on compatible devices |
| Legacy fit | Very common | Requires compatible equipment |
| New designs | Evaluate carefully against risk | Strong option when properly configured (IEC 60839-11-5) |
Wiegand is unencrypted and unidirectional — acceptable inside a cabinet, a liability across a building. Stating “OSDP supported” does not prove Secure Channel is enabled. IP connects controllers to software; RS-485 often carries reader or peripheral buses — design for length, topology, addressing, segmentation and grounding.
Electronic locks, monitoring and life safety
| Lock type | On power loss | Holding force | Best use |
|---|---|---|---|
| Maglock (electromagnetic) | Fail-safe: releases | 300–1,200 lb (≈1,200–5,400 N); 600 lb common indoors | Escape doors and main entrances |
| Electric strike | Usually fail-secure | Depends on the original latch | Interior office doors |
| Electric bolt | Usually fail-secure | High | Store rooms and strong rooms |
| Motor / electrified lockset | Configurable | High | Heavy doors, high-cycle traffic |
Fail-safe releases on lock power loss; fail-secure remains secured from the protected side. Fail-safe does not mean the door is automatically safe in every respect, and fail-secure does not mean occupants may be trapped. Life safety outranks security on any escape route.
Fire alarm interface. BS 7273-4 defines release categories — from actuation by detection in the room served (Category A) to a building-wide alarm with removal of power to the lock (Category B). The door must release on alarm, on a break in the release circuit, and on power loss — with a green break-glass beside the door, a REX within roughly 1–1.5 m, and EN 179 / EN 1125 panic hardware where the door is a designated panic exit. Never assume a software setting alone satisfies code.
Per door: door contact (forced-open, held-open, status); REX (button or motion — not a substitute for compliant emergency egress); emergency release; monitored alarms for invalid credentials, controller tamper, communication failure, lock/PSU fault and emergency release activation where supported. Maglocks typically draw 0.3–0.5 A at 12/24 V — a local PSU at the door outperforms a long 12 V run from a central supply.
Access levels, schedules and security rules
Hardware controls the door; software defines who may use it. Define clear processes for issuing, replacing, suspending and revoking credentials. Access levels group doors with schedules and permissions by role. Access schedules control when entry is permitted; work shifts define how attendance time is evaluated — do not confuse them.
Anti-passback enforces entry/exit sequence rules and needs readers on both sides where applicable; poorly designed rules inconvenience legitimate users when exits are unmonitored. Other advanced functions — occupancy counting, interlocking/mantrap, elevator floors, mustering, visitor management, lockdown, dual authorization — must be specified and tested, not assumed.
High-flow entrances may use turnstiles or speed gates: tripod 30–40 persons/min, full-height 12–20, optical speed gates 30–60 on paper; plan on 60–70% of the rated figure in a real lobby.
Time & Attendance in detail
Attendance software converts clocking events into workforce records: fixed/flexible/rotating/overnight shifts, grace periods, late/early rules, breaks, overtime, holidays, missing punches and approved corrections. The terminal records the event; the attendance engine calculates the outcome.
Confirm before quoting: attendance software or licence; employee and department management; shift and work-rule configuration; reports and export formats; HR/payroll integration; user and event capacity; backup and retention; support. A hardware-only quotation fails if software, licences, configuration and integration are missing. Volume example: 1,000 staff × 2 punches = 2,000 events/day ≈ 500,000/year — plan storage and archiving.
Integration
CCTV / VMS — associate access events with camera views; verify interfaces, camera mapping, timestamp sync, licensing and operator workflow. Intrusion alarm — controlled arming/disarming workflows must not disarm protected areas merely because a credential is presented. Fire alarm — defined door-release behaviour per life-safety design. BMS — selected monitoring or status exchange with clear control authority. HR/payroll — define fields, employee IDs, transfer frequency, exception handling and responsibility for discrepancies.
Design workflow and BoQ essentials
- Site survey — door type, lock, frame, entry/exit, security level, power, network, environment, fire rating, egress, existing interfaces.
- Define functionality — door count, credentials, T&A, visitors, offline operation, integrations, elevators/gates, reporting retention.
- Select door hardware for the actual door and egress — not force rating or price alone.
- Select readers and credentials; consider OSDP for new work where supported.
- Calculate controller capacity — readers in both directions double the count; verify manufacturer limits.
- Design power and cabling — operating and peak lock current, voltage drop, PSU capacity, backup, separation of lock and reader power, grounding, network.
- Define software, licences and integrations.
- Prepare BoQ and submittal with programming, commissioning, training and documentation.
A reader is not a complete door solution. The BoQ must cover controller, lock, power, door monitoring, exit/emergency arrangement, software, licences, cabling/enclosures and services.
Power example: 8 maglocks × 0.5 A = 4 A at 12 V. A 5 A supply leaves no margin for battery ageing — specify 6–8 A or split across two supplies with batteries. Keep copper channels within TIA-568 (100 m); keep power separate from data; use twisted pair for OSDP.
Recommended priorities by application
| Application | Typical design priorities |
|---|---|
| Small office | Simple credentials, reliable hardware, basic logs |
| Corporate / multi-site | Central or cloud management, access levels, scalable controllers, resilience |
| Server room / restricted IT | Stronger credentials, detailed audit, monitoring, dual factor |
| Factory / warehouse | Durable hardware, environment, shift workflows, operational zones |
| Hospital / school / campus | Role-based access, visitors, emergency planning, multi-building admin |
| Employee attendance | Suitable terminals, shift rules, reports, HR/payroll integration |
Relevant references for specification (verify current editions and local adoption): IEC 60839-11 series, IEC 60839-11-5 (OSDP), applicable building and fire codes, data-protection rules for biometrics and attendance, and cybersecurity policies for controllers and credentials.
Check that it works
- Every reader and controller accepts authorised credentials and rejects unauthorised ones on the programmed schedule.
- Door contacts report forced-open and held-open; REX and emergency egress release the lock as designed.
- Fail-safe / fail-secure behaviour matches the approved life-safety design, including fire-alarm release.
- Controllers continue offline as specified; events sync after the network returns; time is synchronised.
- Integrations (CCTV, intrusion, fire, BMS, payroll) meet the acceptance criteria written into the offer.
- For T&A: overnight shifts, grace, overtime, missing punches, exceptions and payroll exports pass a sample run.
Common problems and how to fix them
Maglock on an escape door with no break-glass, REX or fire release
Add compliant emergency egress and fire release per BS 7273-4 and the approved strategy. Life safety outranks security on escape routes.
Fail-secure strike on the only exit from a floor
Respecify for fail-safe release or a compliant mechanical egress path so occupants cannot be trapped on power loss or alarm.
Treating every biometric terminal as a full door controller
Check I/O, lock interfaces, door monitoring and topology. A T&A terminal may lack the door hardware path a controlled door needs.
Wiegand over a long run, or “OSDP” without Secure Channel
Shorten or protect Wiegand runs; for new work prefer OSDP with Secure Channel enabled and verified on compatible devices.
Lock and reader on the same PSU
The reader resets when the lock fires. Separate lock and reader power; size the lock supply for peak current with battery margin.
No door contact
Forced-door and held-open never operate. Fit a supervised door contact and test both alarm conditions.
Assuming all cards are compatible by frequency alone
Confirm technology, format, encryption and reader/controller fit. Do not specify 125 kHz or MIFARE Classic for new security-critical doors.
Confusing access events with attendance records
Keep access schedules and work shifts separate in software and in the offer. Agree attendance rules in writing before go-live.
Ignoring offline operation, cybersecurity and default passwords
Change admin credentials, apply firmware updates, document offline buffering and recovery, and restrict remote access.
Quoting “integrate with CCTV” without scope
Define events, camera map, licences and acceptance criteria. Leave spare controller ports for the next door.
Frequently asked questions
Is access control the same as Time & Attendance?
No. Access control decides and records who may enter. Time & Attendance calculates working hours for HR and payroll. One terminal may do both only when hardware, software and reporting are designed for both.
Should new projects use DESFire or 125 kHz proximity?
DESFire EV2/EV3 is the default for new work. 125 kHz proximity is easily cloned and belongs only on low-risk unsupervised internal doors, if at all.
Why prefer OSDP over Wiegand?
OSDP is bidirectional, supports supervision and Secure Channel when enabled. Wiegand is unencrypted and one-way — usable inside a cabinet, risky across a building.
What is fail-safe versus fail-secure?
Fail-safe releases the lock on power loss; fail-secure stays locked from the protected side. Escape routes need a life-safety release design — never assume a software setting alone meets code.
Can one quotation cover doors and payroll attendance?
Yes, when the BoQ includes controllers, locks, power, monitoring, software, licences, T&A rules and HR export — not readers alone. Hardware-only quotes fail when software and integration are missing.
Talk to PSS about access control
PSS designs, installs and maintains access control and time attendance from single doors to multi-site deployments. Contact the PSS team to book a first site survey.
