Padang-Tua Pejat: A Regional Submarine Cable in Indonesia
The Padang-Tua Pejat submarine cable connects
Padang, a major city on the western coast of Sumatra, Indonesia, to
Tua Pejat, located on the Mentawai Islands. Owned by Telkom Indonesia, the cable spans 160 kilometers and is listed as operational since 2019. It serves as a critical link for regional connectivity between Sumatra and the Mentawai archipelago, facilitating internet and telecommunications services in this geographically challenging area.
What makes this cable particularly interesting is the lack of publicly disclosed technical specifications, such as design capacity, fiber pair count, or supplier details. This absence of information limits the ability to fully assess its technological capabilities, making it an enigmatic yet essential piece of infrastructure for the region.
Quick facts
| Cable name | Padang-Tua Pejat |
| Length | 160 km |
| Ready-for-service year | 2019 (GeoCables database) |
| Owner | Telkom Indonesia |
| Status | In service |
| Design capacity | Not disclosed |
| Fiber pairs | Not disclosed |
| Supplier | Not disclosed |
| Technology | Not disclosed |
| Landing points | Padang (Indonesia); Tua Pejat (Indonesia) |
| Computed latency (one-way) | ≈ 0.8 ms |
| Computed latency (RTT floor) | ≈ 1.6 ms |
Route
The Padang-Tua Pejat cable connects two landing points in western Indonesia: Padang, a bustling coastal city in Sumatra, and Tua Pejat, the administrative center of the Mentawai Islands. The Mentawai Islands are located approximately 150 kilometers off the coast of Sumatra, making submarine cables an essential solution for bridging the geographical divide. The route traverses the Mentawai Strait, a relatively shallow body of water known for its seismic activity, which can pose challenges during cable installation and maintenance.
Why it was built and what it carries
The cable was constructed to address the growing demand for reliable telecommunications and internet connectivity in the Mentawai Islands. As a remote island chain, the Mentawai region faces significant logistical challenges in accessing mainland services. The Padang-Tua Pejat cable provides a direct link to Sumatra, enabling better integration of the islands into Indonesia's broader telecommunications network. It likely carries a mix of voice, data, and internet traffic, although specific details about its traffic profile are not publicly available.
History: what can be established
According to the GeoCables database, the Padang-Tua Pejat cable was ready for service in 2019. No alternative dates have surfaced in publicly available industry sources, so this year is presumed accurate. However, the absence of detailed documentation about the cable's commissioning process or early operational history leaves some gaps in understanding its development timeline.
Capacity and technology
Publicly available sources do not disclose the design capacity, fiber pair count, or specific technology used in the Padang-Tua Pejat cable. Without operator documentation, it is impossible to determine whether the cable employs advanced technologies such as wavelength division multiplexing (WDM) or has been upgraded since its initial deployment. This lack of transparency is not uncommon for smaller regional cables, where operators may prioritize functionality over public disclosure of technical details.
Latency: the physics
The computed one-way light propagation latency for the Padang-Tua Pejat cable is approximately 0.8 milliseconds, based on its 160-kilometer length and the speed of light in fiber (200-204,000 km/s). The theoretical round-trip time (RTT) for the wet segment is around 1.6 milliseconds. However, real-world latency is higher due to additional factors such as land-based network tails, terminal equipment delays, and routing inefficiencies. No live measurements are currently available for this cable, so its actual performance remains unverified.
Redundancy: what happens if it breaks
If the Padang-Tua Pejat cable experiences a fault, redundancy options would depend on alternative infrastructure in the region. While Padang is well-connected to Indonesia's broader telecommunications network, the Mentawai Islands have limited connectivity options. Repairs to submarine cables typically involve deploying specialized cable-laying ships to locate and fix the fault, a process that can be time-consuming and costly, particularly in seismically active areas like the Mentawai Strait. The lack of documented alternative routes for this specific corridor underscores the importance of maintaining the cable's operational integrity.
Bottom line
- The Padang-Tua Pejat cable spans 160 kilometers, connecting Padang and Tua Pejat in western Indonesia.
- Owned by Telkom Indonesia, it has been listed as in service since 2019.
- Key technical details such as design capacity, fiber pairs, and supplier are not publicly disclosed.
- Theoretical latency for the wet segment is approximately 1.6 ms RTT, but real-world latency is higher.
- Redundancy options for the Mentawai Islands are limited, making repairs critical in case of faults.