Technical informational / commercial investigation
Kocom Four-Wire Intercom Cabling and Replacement Guide
Wiring and cabling guide
Confirm the exact equipment models, cable types, power capacity, distances and current manufacturer instructions before installation. Terminal names and ratings vary between products.
Main diagram
Equipment list
- Kocom Door Camera - KC-MC / KC-C family varies by installation
- Existing 4-Core Path - VCC, GND, audio and video functions
- Kocom Indoor Monitor - KCV model label determines exact connector
- Existing Door Lock - Separate release circuit - model dependent
- Cable Identification Test - Photograph, isolate, trace and test every core
- Replacement Path - 2-wire retrofit, new IP cable or like-for-like
Cable schedule
Use the diagram reference to follow the same connection from the main diagram into the detailed explanation below.
| Diagram ref | From | To | Cable type | Core count | Power or data | Maximum distance | Purpose / important notes |
|---|---|---|---|---|---|---|---|
| C1 | Kocom Door Camera | Existing 4-Core Path | Existing four-core cable or Cat5 pairs previously assigned to four analogue functions | 4 functional conductors | VCC commonly documented as 12 V on KCV-544/A374 family | Exact model manual and installed cable | VCC + GND + audio/voice + composite video |
| C2 | Existing 4-Core Path | Kocom Indoor Monitor | Same continuous four-core field path | 4 functional conductors | Model-specific | Exact model manual and cable condition | Legacy door-camera connection |
| C3 | Kocom Door Camera | Existing Door Lock | Separate two-core lock/release wiring where the model and site use a camera-side release | Usually 2 for the documented separate release circuit | AC or DC arrangement depends on the Kocom model and installed lock | Voltage-drop and lock design | Model-dependent separate door-release path |
| C4 | Existing 4-Core Path | Cable Identification Test | Existing cable under test | Record all available and spare cores | Test de-energised unless an authorised procedure requires otherwise | Measure route and continuity | Identify cable type, topology, joins and condition |
| C5 | Cable Identification Test | Replacement Path | Reuse suitable cores for an approved 2-wire design, or install Cat5e/Cat6 for IP/PoE | Replacement-system dependent | Replacement-system dependent | Replacement manual and tested cable | Choose replacement after cable test |
No maximum distance is invented. Where the exact figure depends on Ethernet design, voltage drop, current draw or the selected device, the schedule tells the installer to confirm it.
What the wiring actually is
Match each C reference to the same label on the main diagram and cable schedule. The line name alone is not a complete cable specification, so this table explains the physical cable, conductor or pair use, what it carries and how it normally terminates.
| Diagram ref | Cable shown | Physical path | Cable construction | Conductors or pairs | What it carries | Normal termination | Confirm before installation |
|---|---|---|---|---|---|---|---|
| C1 | Existing four-core cable or Cat5 pairs previously assigned to four analogue functions | Kocom Door Camera to Existing 4-Core Path | Project-specific low-voltage cable selected for the named circuit; do not use a diagram label as a cable specification. | Provide the number of conductors needed for power, signal, supervision and spares after reading both device manuals. | The control, data or device function named in the diagram. | Only the exact labelled terminals in the current manuals. | Cable construction/gauge, conductor functions, polarity, load, voltage drop, topology, distance, separation and required fail state. |
| C2 | Same continuous four-core field path | Existing 4-Core Path to Kocom Indoor Monitor | Project-specific low-voltage cable selected for the named circuit; do not use a diagram label as a cable specification. | Provide the number of conductors needed for power, signal, supervision and spares after reading both device manuals. | The control, data or device function named in the diagram. | Only the exact labelled terminals in the current manuals. | Cable construction/gauge, conductor functions, polarity, load, voltage drop, topology, distance, separation and required fail state. |
| C3 | Separate two-core lock/release wiring where the model and site use a camera-side release | Kocom Door Camera to Existing Door Lock | Normally a dedicated two-core low-voltage control pair for a dry contact; use additional cores where power, supervision or status feedback is required. | A relay uses COM with NO or NC as selected by the required normal/fail state. The relay contact must not be mistaken for a power source. | A command, status or release state. Lock/gate operating power normally comes from a separate correctly sized supply path. | Exact relay and receiving input terminals from both current manuals; fire/egress interfaces require the approved project design. | NO/NC logic, voltage/current rating, wet versus dry input, supervision, required fail state and fire/egress compliance. |
| C4 | Existing cable under test | Existing 4-Core Path to Cable Identification Test | No permanent system cable is implied. Isolate the old equipment and inspect/test each existing conductor safely. | Record every available conductor and twisted pair; test continuity, shorts, insulation/condition and joins. | Diagnostic measurements only. | Temporary test connection appropriate to the isolated circuit. | Whether mains is present, conductor identity, cable condition and whether the cable can meet the proposed replacement manual. |
| C5 | Reuse suitable cores for an approved 2-wire design, or install Cat5e/Cat6 for IP/PoE | Cable Identification Test to Replacement Path | Solid-copper Cat5e or Cat6 balanced Ethernet cable; Cat6 is the normal new-install choice. Do not use copper-clad aluminium. | Four twisted pairs / eight conductors, terminated consistently to T568A or T568B at both ends. | Ethernet data plus IEEE 802.3 PoE power when both the source and device support the required PoE class. | RJ45 plug, keystone or patch panel appropriate to the cable type; preserve pair twists. | 90 m permanent link / 100 m channel, PoE class, total switch budget, surge exposure and voltage drop for high-power devices. |
What "security cable" means
Security cable is a trade description, not a complete specification. On these pages it means multicore, stranded, full-copper extra-low-voltage alarm/access cable. A common Australian product is described as 14/0.20, approximately 0.44 mm2 per conductor, or nominal 0.5 mm2. The installer must still specify core count, conductor area, copper construction, twist/shield requirement, jacket/environment rating and permitted route. It is not Cat5e/Cat6, mains cable, fire-rated cable or automatically suitable for lock power.
| Cable description | Typical use | Important limitation |
|---|---|---|
| 2-core stranded copper | A simple unpowered contact, dry-contact trigger or separately designed DC power pair | Not enough for a powered PIR that also needs an alarm-contact pair. For lock power, calculate conductor size from voltage, current, inrush and distance. |
| 4-core stranded copper | Common for one powered PIR: positive and negative supply plus two alarm-loop conductors; also used for some proprietary four-wire keypad/module buses | Four cores do not define the function or resistor. Label both ends and follow the panel/device manual. |
| 6-core or 8-core stranded copper | Powered devices needing alarm, tamper, auxiliary functions or useful spare conductors | Do not join spare conductors to increase current capacity unless the equipment/cable design explicitly allows it. |
| Twisted or shielded security/bus cable | RS-485/OSDP and other buses only where the manufacturer specifies impedance, twist and shield treatment | Ordinary alarm cable is not automatically a compliant RS-485, OSDP or Ethernet cable. |
| Heavier two-core lock/power cable | Electric strikes, maglocks, sirens or other higher-current ELV loads | Common 0.5 mm2 alarm cable may be too small. Select 1.0 mm2, 1.5 mm2 or another size only after a voltage-drop and inrush calculation. |
Core colours are identification aids only; they do not create a universal positive, negative, zone, tamper or data standard.
Are any resistors required?
| Circuit | Resistor required? | Where it belongs | How to select it |
|---|---|---|---|
| Existing alarm zone | Maybe; preserve and measure the fitted resistor before disconnection | Normally at the field device | Compare the old panel programming and replacement manual. Resistor values are not interchangeable between brands. |
| Existing intercom/audio/video/power conductor | Normally no alarm EOL resistor | Not applicable | Do not mistake a video termination, suppression device or electronic component for an alarm-zone EOL resistor. |
Never choose a resistor by cable colour or by the phrase "security cable". First identify the exact input, panel model and programmed supervision mode. An EOL resistor belongs at the end of the supervised circuit; placing it across the panel terminals defeats cable supervision.
What existing Kocom four-wire cabling usually looks like
| Existing function | What it normally did | Replacement warning |
|---|---|---|
| VCC / 12 V | Power sent from the indoor monitor/system toward the door camera on documented KCV-544/A374 paths | Polarised. Do not connect to a replacement until its voltage and function are confirmed. |
| GND | Common return for the legacy door-camera electronics | Must stay paired with the correct supply and signal reference. Do not identify it from colour alone. |
| AUDIO / VOICE | Analogue speech path between door camera and monitor | Not an Ethernet data conductor and not directly compatible with a modern IP device. |
| VIDEO | Analogue composite-video path from the door camera | Not an IP camera stream. Cable quality, joins and interference affect the old picture. |
| Separate lock pair | Door-opener or lock-release circuit | May run to the camera or monitor depending on model. Confirm AC/DC type, voltage, current and release behaviour. |
| Optional apartment/lobby conductors | Lobby phone, guard phone, sub-monitor or building-system functions | Applies to some apartment models. Identify the complete building topology before replacing an individual monitor. |
Do not use wire colour as proof. The KCV-A374 brochure gives one factory colour example, but installers may have used alarm cable, telephone cable or Cat5 with completely different colours. Photograph both ends and label every conductor before removal.
Kocom models and the differences that matter
| Model family | Documented system type | Typical four-wire information | What to check before replacement |
|---|---|---|---|
| KCV-544 | Polarised four-line door-camera wiring | VCC 12 V, GND, VOICE and VIDEO | Kocom lists KC-MC30, KC-MC24, KC-C60 and KC-MC20 door cameras. The monitor specification includes AC mains input, so isolation and licensed work may apply. |
| KCV-A374 / KCV-A372 / KCV-D372 | Four-wire colour video system | VCC, GND, AUDIO and VIDEO | Manufacturer brochure example uses B=VCC, Y=GND, R=Audio and W=Video, but field cable colours may differ. Supports model-dependent camera, sub-monitor and lock arrangements. |
| KCV-340 | Listed by Kocom under four-wire apartment systems | Confirm the exact KCV-340 manual and connector | Do not transfer the KCV-544/A374 connector order without checking the KCV-340 manual. |
| KCV-504/D504 and KCV-544SD/D544SD | Listed in Kocom's four-wire apartment-system library | Usually a four-wire family path, but exact connector and apartment functions vary | Check whether the installation is a simple villa door camera or part of a shared apartment/lobby system. |
| KCV-464/D464 | Four-wire apartment-system family with lobby/guard integration options | Building topology may include more than one private door-camera cable | Treat shared lobby or guard-phone cabling as a building-wide system, not a simple one-door replacement. |
Compare the existing cable with replacement alternatives
| What you find onsite | Likely replacement direction | Current Security Wholesalers examples | Checks before ordering |
|---|---|---|---|
| Healthy four-core intercom/security cable | Modern two-wire retrofit may be practical using one approved pair | Hikvision DS-KIS702Y-P, Dahua DHI-KTX01(S), or an Akuvox R20A-2/C313W-2 design | Confirm gauge, distance, joins, topology, distributor/switch and polarity rules. Do not assume the spare cores can carry the lock without a separate design. |
| Genuine Cat5e/Cat6 with all four pairs continuous | New IP/PoE intercom may be possible after cable certification and correct RJ45 termination | Current Hikvision, Dahua or Akuvox IP intercom kit | Old Kocom installers sometimes allocated Cat5 pairs to analogue functions. Remove any pair doubling, joins or non-Ethernet terminations and test all four pairs. |
| Damaged, joined, wet or unidentified cable | Do not promise reuse | Install new Cat6 or a manufacturer-approved new two-wire route | The labour saved by reuse is not worth an intermittent call, video or unlock path. |
| Separate two-core lock cable in good condition | May be reusable for the new release path after assessment | Strike, gate input or lock PSU appropriate to the replacement | Confirm voltage drop, lock current, fail mode, relay/load ratings and egress requirements. |
| Shared apartment/lobby Kocom system | Individual villa-kit replacement is usually not a direct substitute | Building-wide intercom assessment | Map risers, distributors, lobby panel, guard station, unit monitors and release logic before selecting products. |
This comparison is the purpose of the guide: identify the real cable first, then shortlist only the modern systems whose documented cabling requirements match it.
Quick replacement decision
- Read and photograph the exact Kocom monitor and door-camera model labels.
- Photograph every connector before unplugging it.
- Determine whether the job is a private one-door system or part of an apartment/lobby network.
- Identify the four intercom functions and trace any separate lock pair.
- Inspect the printed cable sheath where accessible: four-core security cable and Cat5e/Cat6 lead to different options.
- Test continuity, shorts, joins and spare cores with all equipment safely isolated.
- Compare the result with the replacement table above.
- Confirm the chosen replacement manual, distance, topology, power and lock interface before ordering.
Before disconnecting the old Kocom equipment
Some Kocom indoor monitors, including the documented KCV-544, have an AC mains power input. Do not remove a monitor from the wall or touch supply wiring until the supply arrangement is identified and safely isolated. Fixed 230-240 VAC work must be handled by an appropriately licensed electrician. Keep the four low-voltage intercom functions separate from mains and from the door-lock circuit.
How the original four-wire path worked
The monitor powered the compatible Kocom door camera and exchanged analogue voice and composite video over four polarised functions. That is fundamentally different from a modern two-wire IP-over-bus system or Cat5e/Cat6 Ethernet. A replacement product cannot be connected function-for-function unless its manufacturer explicitly supports that legacy interface.
Common Kocom replacement mistakes
- Assuming blue, yellow, red or white conductors always represent the factory KCV-A374 colour example.
- Crimping an RJ45 plug onto four used Cat5 conductors without proving all four twisted pairs are intact and suitable for Ethernet.
- Counting the lock pair as part of the four monitor-to-camera functions.
- Buying a two-wire kit before checking cable joins, gauge, distance and topology.
- Replacing one apartment monitor without checking whether it belongs to a shared lobby or guard-phone system.
- Disconnecting a mains-powered indoor monitor without identifying and safely isolating its supply.
What the existing wiring tells you
| What you find | What it probably means | Next check | Replacement implication |
|---|---|---|---|
| Four conductors plus a separate two-core cable at the door | Normal villa-style Kocom intercom path plus a separate release circuit | Trace VCC, GND, audio, video and lock pair independently | Two-wire retrofit may reuse a suitable pair; lock path still needs its own design |
| Eight-conductor Cat5 cable with pairs doubled at the old connector | Cat5 may have been used as analogue intercom cable rather than Ethernet | Disconnect safely and test all four twisted pairs end-to-end | IP/PoE may be possible only after full retermination and cable testing |
| More conductors, riser wiring or lobby/guard connections | Apartment/shared-entry Kocom architecture | Identify distributors, lobby panel, guard station and every dwelling served | Do not substitute a simple villa kit for one unit |
| Picture or audio was intermittent before failure | Cable joint, corrosion, damaged core, poor connection or failing equipment | Test cable independently of the old electronics | Prefer new cable if reuse cannot be proven reliable |
| Door unlock works on a separate pair | Dedicated release circuit is present | Identify lock type, voltage, current and where power originates | The pair may be reusable after voltage-drop, relay and egress review |
Compatible products and categories
Confirmed live product page
Confirmed live product page
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Exact product links above were confirmed on the current Security Wholesalers site on 2026-07-19. Category links are used when an exact active compatible product was not confirmed.
Related diagrams
Frequently asked questions
What are the four wires on an older Kocom video intercom?
For documented KCV-544 and KCV-A374-family systems, the four functions are VCC or 12 V supply, ground, audio/voice and composite video. Do not rely on installed cable colours alone; trace the functions and confirm the exact model manual.
Can the existing Kocom four-core cable run Ethernet or PoE?
Not automatically. Ordinary four-core intercom or security cable is not Ethernet cable. If the installed cable is genuine Cat5e or Cat6 with all four twisted pairs intact, it may be suitable for an IP design after testing and retermination. Four visible conductors at the old connector do not prove that.
Can a two-wire intercom reuse the old Kocom four-wire cable?
Often one suitable pair can be allocated to an approved two-wire retrofit system, leaving other cores spare or available for a separately designed function. Reuse still depends on cable gauge, condition, joins, topology, distance and the exact Hikvision, Dahua or Akuvox equipment.
Is the Kocom door-lock wiring part of the four intercom wires?
Usually the lock or opener uses a separate circuit. On KCV-A374-family diagrams the release can be associated with the monitor or door camera depending on the door and hardware. Photograph and trace the lock pair separately rather than assuming it is included in VCC, ground, audio and video.
Which current systems should be compared after identifying the cable?
Compare the tested cable and site topology with current Hikvision, Dahua and Akuvox two-wire or IP intercom requirements. The guide links to current Security Wholesalers examples, but the final selection must match the actual cable gauge, distance, joins, lock circuit and number of stations.
Can one apartment replace only its Kocom monitor?
Do not assume so. A unit connected to a shared lobby panel, riser, distributor or guard station is part of a building-wide system. Identify the complete Kocom architecture before choosing a replacement; a private villa kit is not automatically compatible.
Technical references
| Manufacturer | Document | Revision | Relevant pages | Reference | Accessed |
|---|---|---|---|---|---|
| Kocom | KCV-544 Operating and Installation Manual | English manual | Specifications and door-camera wiring | Official/source reference | 2026-07-19 |
| Kocom | KCV-A374 / A372 / D372 four-wire system brochure and wiring diagram | Manufacturer brochure | Four-wire system wiring diagram and lock arrangements | Official/source reference | 2026-07-19 |
| Kocom | Kocom four-wire apartment-system manual library | Current support library | KCV-340, KCV-504/D504, KCV-544, KCV-544SD/D544SD, KCV-A374/D374 and related models | Official/source reference | 2026-07-19 |
Diagram revision: 1.1. Confirm the exact current manual for the selected equipment before installation.
Australian installation and safety notice
General guide only. Confirm current manufacturer instructions and site requirements. Work involving 230-240 VAC must be completed by an appropriately licensed electrician. Fire-release interfaces, emergency exits and door locking require project-specific compliance assessment. Keep mains and ELV cabling appropriately separated, isolate power before work, observe battery polarity and calculate voltage drop for the real load and cable run.