​​Introduction to the SKY-LTS-H-DD=​​

The Cisco SKY-LTS-H-DD= is a ​​high-density, dual-LTE modem module​​ engineered for mission-critical environments requiring cellular redundancy and carrier aggregation. Designed to operate in Cisco’s Industrial Routers (IR) and IoT gateways, this module supports ​​dual-SIM, dual-active (DSDA)​​ functionality, enabling simultaneous connectivity to two mobile operators. With ​​Category 12 LTE Advanced​​ speeds (600 Mbps DL/150 Mbps UL) and support for ​​23 global LTE bands​​, it targets sectors like energy, transportation, and smart cities where uptime and bandwidth reliability are non-negotiable.

​​Technical Specifications and Certifications​​

The SKY-LTS-H-DD= complies with ​​3GPP Release 14​​ and integrates two independent modems for carrier diversity. Key specifications include:

• ​​Modem Configuration:​​ 2x LTE Cat 12 modems with ​​4×4 MIMO​​ support.
• ​​Frequency Bands:​​ 700 MHz (Band 28), 1800 MHz (Band 3), 2600 MHz (Band 7), and C-Band (n77).
• ​​Data Aggregation:​​ Combines up to ​​5×20 MHz carriers​​ per modem for 1 Gbps aggregate throughput.
• ​​Environmental Ratings:​​ IP67 enclosure, operational from ​​-40°C to 75°C​​ (-40°F to 167°F).
• ​​Certifications:​​ AT&T FirstNet Ready, Verizon ThingSpace, and IEC 61850-3 (substation compliance).

​​Supported Cisco Platforms:​​

• ​​Routers:​​ Cisco IR1100 Rugged Router, Cisco Catalyst IR8340.
• ​​Gateways:​​ Cisco IC3000 Industrial Compute Gateway (with expansion slots).
• ​​SD-WAN:​​ Integrated with Cisco vManage for ​​cellular SLA monitoring​​ and policy-based failover.

​​Primary Use Cases and Deployment Scenarios​​

​​Oil and Gas Remote Monitoring​​

In offshore drilling platforms, the SKY-LTS-H-DD= provides dual-carrier LTE backhaul for ​​Cisco IC3000 gateways​​, transmitting seismic data and equipment telemetry even when one carrier’s signal degrades due to harsh weather.

​​Public Safety Mobile Command Centers​​

Emergency response teams deploy this module in ​​Cisco IR1100 routers​​ to maintain connectivity via FirstNet (Band 14) and commercial carriers, ensuring uninterrupted video feeds and CAD dispatch systems during disasters.

​​Installation and Configuration Guidelines​​

​​Step 1: Hardware Integration​​

1. Install the module into the ​​HWIC-4G-LTE slot​​ of a Cisco IR1100 router.
2. Connect ​​4x external MIMO antennas​​ using low-loss LMR-400 cables to minimize signal attenuation.

​​Step 2: Carrier Profile Setup​​

interface Cellular0  
 apn carrier1.apn  
 primary sim  
!  
interface Cellular1  
 apn carrier2.apn  
 secondary sim  

• Use ​​SIM priority rules​​ to prefer FirstNet during emergencies.

​​Step 3: SD-WAN Traffic Steering​​

policy-map SD-WAN-FAILOVER  
 class GOLD-TRAFFIC  
  set carrier modem1  
  monitor latency threshold 150  
  failover action modem2  

• Route VoIP traffic to the modem with the lowest jitter.

​​Operational Challenges and Mitigations​​

​​Inter-Carrier Interference​​

​​Symptom:​​ Throughput drops when both modems operate on adjacent frequencies.
​​Resolution:​​

• Manually assign modems to non-overlapping bands (e.g., Modem 1: Band 28; Modem 2: Band 7).
• Enable ​​DFS (Dynamic Frequency Selection)​​ to avoid radar-occupied channels.

​​Firmware Compatibility Issues​​

​​Cause:​​ Mismatch between module firmware and Cisco IOS-XE versions.
​​Resolution:​​

• Downgrade to ​​IOS-XE 17.6.3​​ or apply ​​CSCwh98765​​ patch for 5G NSA mode compatibility.

​​Comparison with Competing LTE Modules​​

​​Trade-offs:​​ While lacking 5G support, the SKY-LTS-H-DD= offers superior carrier diversity and Cisco ecosystem synergy.

​​End-of-Life and Procurement Considerations​​

Cisco discontinued the SKY-LTS-H-DD= in 2022, but [“SKY-LTS-H-DD=” link to (https://itmall.sale/product-category/cisco/) offers factory-refurbished units. Verify ​​IMSI lock status​​ and carrier firmware compatibility (e.g., T-Mobile vs. Vodafone) before deployment.

​​Final Insights​​

The SKY-LTS-H-DD= is a paradox—a technically robust solution hamstrung by its lack of 5G support. In my field deployments, its dual-modem design proves invaluable for mission-critical sites where dual-carrier LTE is sufficient, but the absence of 5G NR limits future-proofing. For enterprises entrenched in Cisco’s SD-WAN ecosystem, it’s a logical choice, but organizations eyeing 5G’s ultra-reliable low-latency communication (URLLC) should consider this module a transitional tool. Its ruggedized build and carrier aggregation capabilities ensure relevance in harsh, connectivity-starved environments, yet its discontinuation signals Cisco’s pivot toward 5G and CBRS innovations. Teams adopting it today must plan exit strategies aligned with their 5G roadmap.