EM Lock With LED, Feedback and Timer: When You Need Each Feature

Short answer: a plain EM lock is enough for most single doors with a reader. Add an LED when people need to see whether the door is locked, feedback (a door-status output) when a controller, alarm or interlock must know the door is actually shut, and a buzzer or timer when doors get propped open. On our store these models cost ₹1,600 to ₹2,450 for 600 lbs, against ₹1,499 for the EM-602.

What does the LED on an EM lock do?

The LED is a status light on the lock body, usually one colour when the magnet is holding and another (or off) when it releases. It tells the person at the door when to push, which saves the frustrated tugging you see at busy glass doors. It also helps an electrician: if the light shows locked but the door still opens, the problem is the plate alignment, not the power.

On our store, the SecureEye 600 lbs lock is sold with an LED, the EM-605BT lists a dual LED, and the EMDL-1202 double-leaf lock lists LED indication.

What is feedback on an EM lock?

Feedback is an extra pair of contacts inside the lock that reports its status to other equipment. Depending on the model it reports whether the door is closed against the magnet or whether the lock is holding. The lock still works the same way; feedback simply adds information.

You need feedback when something else must react to the door:

• Door interlocking. In pharma airlocks and cleanrooms, the controller only opens door B after door A reports closed and locked. Without feedback, interlocking cannot work. See our door interlocking guide.
• Door-held-open or forced-door alarms. A reader or alarm panel with a door-sensor input can raise an alarm if the door is left open or forced.
• Monitoring from a control room or app. The status contact can feed an alarm zone or a Wi-Fi sensor input.

Our EM-305 (300 lbs) and EM-605 (600 lbs) are sold as feedback locks. The EM-602 listing states a monitored door sensor and an inbuilt relay, and the EM-605BT lists an inbuilt door sensor with a 5-point terminal.

What do the buzzer and timer do?

A buzzer sounds to signal door status. The EM-605BT listing states an inbuilt buzzer for door status indications. In practice this is used to nag people who leave a door open: air-conditioned rooms, server rooms, stores and pharmacy cold rooms where a propped door costs money.

A timer controls how long something happens. The EM-605BT is sold as a lock with buzzer and timer, but its listing does not state the timer range or exactly what it times, so ask us before buying if the timer is the reason you want it. The EM-605 listing separately describes a delay switch feature. Remember that the main door-open time (how long the lock releases after a valid card) is normally set on the reader or power supply, not the lock. The WP-25 keypad, for example, lists an adjustable door relay time of 0 to 99 seconds.

What is anti-residual magnetism?

After a strong magnet releases, a little magnetism can linger and make the plate stick for a moment. Locks designed against residual magnetism let go cleanly the instant power is cut. The EM-605BT listing states an anti-residual magnetism design. It matters most on light doors and on doors used by children or elderly people who push gently.

Which features does each lock on our store list?

Combo-CN157 is a kit: the listing includes an EM-602 lock, a 12 V adapter, a PSW-44 exit button and L and Z brackets. The EM-605 and EMDL-1202 have limited stock, so check availability.

When do you need each feature?

• Single office or cabin door with a card reader: a plain lock is enough. The EM-602 (₹1,499) already includes a door sensor if you want it later.
• Busy glass entrance, showroom or clinic: an LED, so visitors know when to push. SecureEye with LED (₹1,800).
• Pharma airlock, cleanroom or any interlocked door: feedback is essential. EM-605 (₹1,600), or one of our interlocking kits, which include feedback or door-sensor locks.
• Server room, store room or cold room that gets propped open: buzzer and door sensor. EM-605BT (₹2,450).
• Door connected to a burglar alarm: feedback, wired to an alarm zone.

The extra feature costs about ₹100 to ₹950 per door over the plain EM-602, so it is worth buying only where something will actually use it.

How are the extra wires connected?

The two power wires connect exactly as on a plain EM lock, through the reader's COM and NC contacts. The feedback or door-sensor contacts go to the reader's door-sensor input, an interlock controller, or an alarm panel zone. If nothing will read them, leave them unconnected; the lock works normally. The full steps are in how to wire an EM lock with a reader and exit switch.

For prices across every size, see the EM lock price guide; for choosing a size and bracket, the EM lock buying guide. Browse EM locks with LED, feedback or timer and all EM locks, or build a door in the access control kit builder.

FAQ

What is a feedback EM lock?

It is an EM lock with an extra status output that tells a controller or alarm whether the door is closed or the lock is holding. It is needed for door interlocking and door-open alarms.

Do I need an EM lock with LED?

Only if people need to see the lock status, such as on busy glass doors. For a staff-only cabin door, a plain lock works just as well.

What is the price of an EM lock with feedback?

On our store the EM-305 (300 lbs) with feedback is ₹1,799 and the EM-605 (600 lbs) with feedback is ₹1,600. The EM-602 with a monitored door sensor is ₹1,499.

What does the timer on an EM lock do?

It depends on the model. The EM-605BT listing names a timer but does not state its range, so ask us before ordering. The door-open time after a card is normally set on the reader.

Can I use a feedback lock without connecting the feedback wires?

Yes. The lock holds and releases normally on its two power wires. The feedback contacts are only used if a controller or alarm reads them.

Which EM lock is best for door interlocking?

One with feedback, such as the EM-605. Our 8-door interlocking kit Combo-CN36 includes eight EM-605 locks.

Prices are NavKar Systems website prices on 27 October 2026, inclusive of GST, and may change.