# Industrial NTP Time Server — Product Specification (Shipping)

| Item | Content |
|------|---------|
| **Audience** | Agents / end customers / tender package |
| **Document title** | Product Specification (Shipping) |
| **Doc No.** | `DOC-Q3000-DS-EN-011` |
| **Model** | **QYTS-3000-BG-T-S** |
| **Document version** | 1.1 |
| **Firmware** | V4.9.0 (see device label / Web Dashboard Firmware & Build) |
| **Related documents** | User Guide (bid-sanitized); Industrial Interface Protocol (annex) |
| **One-pager** | Selection Sheet (Reference · Policy · Capacity) |

---

## 1. Overview

GNSS-disciplined LAN **NTP Stratum 1** time server providing Ethernet NTP, RS-485 Modbus absolute time, TTL 1PPS output, and IRIG-B120 (this SKU). For industrial, security, office, and auxiliary metrology timing.

| Item | Specification |
|------|----------------|
| Commercial model | **QYTS-3000-BG-T-S** |
| Constellation code | **BG** = BeiDou + GPS (UI may show `BD+GPS`) |
| Oscillator / Power | **T** = TCXO; **S** = single supply |
| Timing protocol | NTP v3/v4 (UDP **123**) |
| Time reference | GNSS 1PPS + TCXO discipline; industrial RTC (temp-compensated) / SQW holdover |
| Management | Web (HTTP Basic Auth) + front-panel LCD; **SNMP read-only** (UDP **161**, SNMPv2c) |
| Identity | Factory SETID (Web / LCD: `SN:`) |

---

## 2. Electrical & Environment (summary)

| Item | Specification |
|------|----------------|
| Power | **Single path `-S`**. Two inlets; **use only one at a time**: (1) **AC 220 V** IEC 3-pin inlet (onboard isolated step-down + filter/rectifier, ≈12.5 V internal rail); (2) **DC-IN (DC050-T)** + external adapter, **12–24 V DC** (see nameplate/adapter). Do not feed AC and DC together. Export: plug/adapter per order. Not dual-redundant (`-D`) |
| Ethernet | **1×** RJ45, 10/100M (single port; not dual-port redundancy) |
| Operating temperature | Per hardware datasheet / nameplate |
| Default IP | **192.168.1.123** / 255.255.255.0 / gateway 192.168.1.1 |

---

## 3. Interfaces

| Interface | Function | Notes |
|-----------|----------|--------|
| RJ45 | NTP + Web | Same IP/MAC; not a second independent port |
| RS-485 | Modbus RTU slave | Absolute UTC time registers (incl. ms) |
| 1PPS OUT | TTL pulse-per-second | Hardware second edge |
| IRIG-B120 | DCLS timecode | Frame output aligned to PPS |
| GNSS antenna | Fix + 1PPS | Outdoor antenna as installed |
| Front panel | LCD + single key | Ops / status display |

---

## 4. Timing Accuracy (by channel)

Metrics of different interfaces **must not be mixed**.

| Channel | Typical capability (after LOCK) | Use |
|---------|----------------------------------|-----|
| Internal / GNSS 1PPS reference | Module short-term ≤ **10 ns RMS**; internal jitter monitor ≤ **50 ns** (short window) | Factory / acceptance reference |
| TTL 1PPS OUT | Sub-microsecond edge (vs internal PPS) | Hardware second-edge sync |
| RS-485 Modbus | **1 ms** resolution | PLC / SCADA absolute time |
| Ethernet NTP | Typical **millisecond** class on LAN (verify on client) | PCs / servers / switches |
| Holdover | Degrades toward ppm with unlock time | Short GNSS outages |

> **Important:** “GNSS 1PPS 10 ns RMS” is **not** “NTP client 10 ns” or “nanosecond Modbus timing.”

---

## 5. NTP Service

| Item | Specification |
|------|----------------|
| Mode | NTP server (RFC 5905 subset) |
| After LOCK | Typically **Stratum 1** |
| Warm-up / policy window | May reply Stratum 2 per Web serve policy (factory default: lock-based serve) |
| Recommended clients | ≤ **60** on LAN |
| Global replies | **Adaptive** rate limit (no low hard cap under normal load); overload protect ≈ ≤ **1024**/s; further derated during large Web exports |
| Per source IP | ≤ **8** replies/s |
| ACL | Optional NTP source IP allow-list (Web) |

**Not included:** PTP/IEEE 1588 stack, NTS, dual-port failover, IPv6, NTP broadcast/multicast server, **HTTPS**, SNMPv3 / SNMP write.

---

## 6. RS-485 Modbus RTU

| Item | Specification |
|------|----------------|
| Link | **9600 8N1** |
| Slave ID | **0x01** |
| Function codes | Read **0x03 / 0x04** (write only for factory use; see protocol annex) |
| Clock registers | UTC Y/M/D/h/m/s/**ms** |
| Poll rate | Recommend ≥ **1 Hz** |

Full register map: Industrial Interface Protocol annex.

---

## 7. 1PPS & IRIG (summary)

| Item | 1PPS OUT | IRIG-B120 |
|------|----------|-----------|
| Level | 3.3 V TTL (per terminal/datasheet) | Per hardware datasheet |
| Role | Second-edge sync | Legacy timecode |
| Absolute time | Pulse = second boundary; calendar via Modbus/NTP | Same |

---

## 8. Management & Logs

| Item | Specification |
|------|----------------|
| Web | Dashboard / Network; Basic Auth |
| SNMP | **Read-only** SNMPv2c, UDP **161**; MIB-II system + device status; **no** Set / SNMPv3 / Trap; enterprise PEN provisional |
| Syslog | **Optional** UDP edge push (default OFF); same dictionary as `event_log`; Web Network configures target IP:514 |
| Event log | `event_log.csv` (`/flog`), ring ~**2048** entries; default export ~**latest 1024**; Dashboard → Diagnostics → Export |
| 24 h quality | `quality_24h.csv` (`/stats24`); hourly buckets; `samples=0` = no GNSS-disciplined samples that hour |
| Front panel | Four pages: patrol / decide / diagnose / asset |

---

## 9. Ordering & Traceability

Record on the shipping sheet:

```text
Model: QYTS-3000-BG-T-S
SETID: _______________
FW_BUILD_ID: _______________
Production test: PASS / FAIL
```

---

## 10. Related Documents

| Document | Content |
|----------|---------|
| Reference · Serve Policy · Capacity (One Page) | Selection Sheet (Reference · Policy · Capacity) |
| User Guide | Power-up, LCD, Web, clients, FAQ |
| Industrial Interface Protocol | Modbus map, IRIG, integration checklist |
| This specification | Contract / selection boundaries |

*This document is a shipping/contract summary. Implementation details follow the annex and the shipped firmware.*