INNO i4 vs i4S Fusion Splicer: Which to Buy?
The INNO i4 and i4S are two of the most popular compact fusion splicers for FTTH and network work in Pakistan. They look similar, both splice in about 4 seconds, and both come from INNO Instrument's i-series. But they use different alignment methods and have very different batteries. This guide explains the real differences so you can choose the right one for your team.
The short answer
- Choose the i4 if you mainly do FTTH drops and short-distance work, want the lightest machine, and want to keep costs down.
- Choose the i4S if you do backbone, distribution or mixed work, need the highest accuracy, and spend long days in the field away from power.
Specifications side by side
| Feature | i4 | i4S |
|---|---|---|
| Alignment | Active V-groove (cladding) | Core alignment |
| Splice time | 4 s quick mode (SM mode about 5 s) | 4 s quick mode |
| Heating time | 13 s | 9–13 s |
| Battery | 3500 mAh, about 200 cycles | 7000 mAh, about 400 cycles |
| Screen | 4.3″ colour touch screen | 5″ colour touch screen |
| Magnification | Up to 320× | Up to 320× |
| Splice memory | 10,000 records and images | 20,000 records and images |
| Weight (with battery) | 1.384 kg | 1.826 kg |
| Size (H × W × D) | 130 × 137 × 132 mm | 145 × 131 × 159 mm |
One cycle means one splice plus one heat-shrink. Figures are from INNO Instrument's published specifications and test reports. INNO's 2024 test report gives the i4S heating time as 9 seconds, and dealer brochures list 13 seconds, so we show both.
Difference 1: alignment method
This is the most important difference.
The i4 uses active V-groove (cladding) alignment. The fibres sit in precision V-grooves, and the machine aligns them by their outer cladding, adjusting their position actively before the arc. For modern G.652.D and G.657 fibres with good core concentricity, this gives low splice loss. INNO quotes typical splice loss of 0.03 dB for single-mode and G.657 fibre, 0.01 dB for multimode, and 0.05 dB for DS and NZDS fibre.
The i4S uses core alignment. Cameras look at the fibre cores themselves and line them up directly. This removes the effect of any small offset between the core and the cladding, so results stay consistent across different fibre brands and types. Core alignment is the usual choice for backbone links, long-haul work and jobs where each splice must be as low-loss as possible.
In a 2024 test published by INNO, the i4S was taken to high altitude in cold and windy conditions. It completed splices without arc calibration, and the splices measured 0.00 dB in both directions on an OTDR.
Difference 2: battery life
The i4S battery is twice the size: 7000 mAh against 3500 mAh. That means about 400 splice-and-heat cycles per charge against about 200.
In Pakistan, where field teams often work on poles and in villages with no reliable power, and where load-shedding is common, this matters. With the i4S, one charge can cover a full day of heavy splicing. With the i4, a busy team should carry a spare battery or a way to charge in the vehicle.
Difference 3: screen, memory and size
The i4S has a larger 5-inch screen, which makes fibre images easier to read in bright sunlight and for older eyes. It also stores 20,000 splice records and images, twice as many as the i4. This is useful for contractors who must hand over splice reports to clients.
The i4 is the lighter and more compact machine, at 1.384 kg against 1.826 kg. If your technicians splice on poles or carry the splicer all day, the lower weight is a real benefit.
What both machines share
- Fast 4-second splicing in quick mode.
- Full touch-screen control.
- Support for common single-mode (G.652 and G.657) and multimode fibres.
- Automatic arc calibration for changes in air pressure and temperature.
- A compact, field-ready design built for FTTH work.
Which one should you buy?
The i4 is right for you if:
- Most of your work is FTTH drops, home connections and short links.
- You are building a team and need several machines on a budget.
- Your technicians value a light, compact splicer.
See the INNO i4 Fusion Splicer.
The i4S is right for you if:
- You splice backbone, distribution or long-distance links where every 0.01 dB counts.
- You work with fibres from many different manufacturers.
- Your team works long days away from power.
- You need to store and share a lot of splice records.
See the INNO i4S Fusion Splicer.
Tips for good splices with either machine
- Use a good cleaver and keep its blade clean and rotated. A poor cleave causes most high-loss splices.
- Clean the fibre with isopropyl alcohol and lint-free wipes after stripping.
- Keep the V-grooves and electrodes clean, and replace electrodes when the machine prompts you.
- Run an arc calibration when you move to a site with very different temperature or altitude.
- Splice in a sheltered spot, such as a vehicle or tent, in wind and dust.
Buying from Litech
We supply genuine INNO fusion splicers with free delivery across Pakistan in 5–7 working days. Warranty is as per INNO's terms. Need fibre cable as well? See our guide on choosing the right fibre optic cable.
Enquiries: WhatsApp +92 313 7776766 or email info@litech.com.pk.
