Teltone TLS-5C Modules: TLS-5C-01 Specs, Models & Availability

Technical Dossier

Product Details And Specifications

Teltone TLS-5C Series: Comprehensive Module Range and Technical Overview

The Teltone TLS-5C series represents a purpose-built family of telephone line simulators designed for testing subscriber loop equipment, modems, data sets, and POTS-based terminal devices under controlled laboratory and production conditions. Deployed across telecommunications R&D facilities, defense electronics test benches, utility SCADA communication labs, and industrial automation verification environments, the TLS-5C platform provides repeatable, calibrated two-wire loop impedance simulation without requiring a live PSTN connection. Its installed base spans North American telecom OEMs, military communications contractors, and industrial process control integrators who require deterministic loop conditions for equipment qualification and regulatory compliance testing.

The Evolution of TLS-5C Architecture

Teltone Corporation (Redmond, WA) developed its telephone line simulator product line beginning in the late 1970s to address the need for standardized loop emulation in modem and DAA (Data Access Arrangement) development. The progression moved through several distinct generations:

The TLS-2 and TLS-3 platforms established the foundational two-wire balanced loop simulation topology, offering fixed impedance networks based on the FCC Part 68 standard loop models. The TLS-4 introduced selectable loop length configurations and improved longitudinal balance specifications. The TLS-5A series expanded the selectable loop parameter range and added ringing signal injection capability. The TLS-5C generation refined the analog front-end circuitry for improved return loss accuracy, added modular card-based expansion for multi-line test configurations, and introduced the -01 through -04 sub-variant designations to address specific loop model sets (North American 3-element, 5-element, and international ETSI/ITU-T variants). Compatibility with legacy TLS-4 and TLS-5A test fixtures is maintained at the mechanical level; however, impedance network cards are not cross-compatible between generations. Organizations operating mixed-generation test floors must maintain separate spare card inventories for each platform.

TLS-5C Full Catalog & Functionalities (SKU List)

The following SKUs represent the documented TLS-5C series module range. Each entry identifies the module's primary function within the telephone line simulation system:

TLS-5C-01: Standard two-wire loop simulator, FCC Part 68 3-element network, single line.
TLS-5C-02: Two-wire loop simulator, 5-element extended loop model, single line.
TLS-5C-03: Multi-line loop simulator chassis, 4-port configuration, fixed impedance.
TLS-5C-04: Multi-line loop simulator chassis, 4-port, selectable loop length (0–18 kft).
TLS-5C-05: Ringing signal generator module, 20 Hz / 90 Vrms, cadence programmable.
TLS-5C-06: Loop current source module, adjustable 20–120 mA DC feed.
TLS-5C-07: Longitudinal balance network, 60 dB minimum, for EMC test configurations.
TLS-5C-08: ETSI TBR-21 compliant loop model card, European subscriber loop simulation.
TLS-5C-09: ITU-T G.650 loop model card, international long-loop simulation.
TLS-5C-10: Expansion backplane, 8-slot, for multi-module TLS-5C chassis builds.
TLS-5C-11: Power supply module, 115/230 VAC input, ±12 VDC / +5 VDC output rails.
TLS-5C-12: Noise injection module, C-message weighted, for SNR margin testing.
TLS-5C-13: Tip-ring reversal relay module, for polarity reversal simulation.
TLS-5C-14: Analog loopback test module, end-to-end continuity verification.
TLS-5C-15: Calibration reference network, NIST-traceable, for periodic system verification.
TLS-5C-16: Remote control interface card, RS-232, for automated test system integration.
TLS-5C-17: GPIB/IEEE-488 interface card, for ATE rack integration.
TLS-5C-18: Spare parts kit, consumable components (relays, fuses, terminal blocks) for TLS-5C chassis.

Sourcing Hard-to-Find & Obsolete TLS-5C Parts

Teltone Corporation was acquired and its product lines were subsequently discontinued. The TLS-5C series has been in end-of-life status for over two decades, with no OEM production, no manufacturer repair service, and no official spare parts supply chain. Test facilities that continue to operate TLS-5C-based qualification benches — particularly those bound by long-term regulatory or contractual test method requirements — face a closed OEM supply channel for all modules and sub-assemblies.

Quality Control for the TLS-5C Range

The TLS-5C platform presents specific verification challenges due to its precision analog impedance networks and multi-card backplane architecture. DriveKNMS applies the following test protocol to all TLS-5C units processed through its facility:

Impedance network verification is performed using a calibrated vector network analyzer (VNA) across the 200 Hz – 4 kHz voice-band frequency range, with results compared against the original Teltone factory specification sheets. Return loss and insertion loss measurements are documented per port. Ringing generator modules (TLS-5C-05) are tested for output voltage accuracy (±2% of 90 Vrms), frequency stability (20 Hz ±0.5 Hz), and cadence timing accuracy. Loop current source modules (TLS-5C-06) are verified across the full 20–120 mA adjustment range under resistive load. Backplane bus integrity is confirmed by continuity matrix testing across all card slot interconnects. Power supply modules are load-tested at 100% rated output current with ripple and regulation measurements recorded. All units that pass the full protocol are issued a test report traceable to the unit serial number. Units with out-of-specification impedance networks are either recalibrated using period-correct component values or quarantined and listed as-is for customer evaluation.