SC901AU / SC902AU (ISF3 range) SIM installation guide

Which SIM does the Daitem ISF3 range take?

A standard size SIM (2FF) in the GSM interface unit. The ISF3 doorphones themselves are radio devices — the SIM lives in the separate GSM module that links the system to the mobile network, not in the door panel. Voice-capable, active, PIN-free.

Which network?

The ISF3's GSM side is 2G-era, so it needs a network still carrying 2G at the property. With those thinning out, a multi-network SIM is the sensible fit: it registers on whichever compatible network remains strongest and re-registers if that changes, keeping the doorphone's outside line alive without a revisit.

Fitting the SIM

For the installing engineer:

1. Power down the GSM interface unit — not the door panel; the SIM isn't there.
2. Fit the standard SIM in the module's holder.
3. Position the module where signal is strongest; unlike a hardwired panel, Daitem's radio architecture gives you placement freedom — use it.

First power-up

Let the module register, pair it with the doorphone system per the installation guide, and test: door call reaches the programmed phone, release works from the handset.

If it won't connect

• No registration: 2G coverage check first — test the SIM in an old phone where the module sits.
• Radio link fine, calls fail: the GSM module side — SIM credit, programming, signal.
• Intermittent: move the module. It doesn't have to live in the worst corner of the house.

FAQ

Where does the SIM go? In the GSM interface module, not the door panel.

Will it survive the 2G switch-off? Not on the GSM side — plan around your area's timeline.

Can the module go anywhere? Within radio range of the system, yes — pick the spot with signal.