Timecode distribution · Firmware 3.1.5
NTP/LTC Converter — your timecode becomes network time, and back
It reads the LTC timecode you already have and answers clocks, PCs and servers on the network as a stratum 1 NTP server. Or the other way round: it takes the time from an NTP server and generates LTC. Powered over Ethernet, it also works on isolated networks, with no Internet, GPS or router.
NTP ⇄ LTC converter, powered over Ethernet
Features
Professional NTP/LTC Converter
- Three modes: LTC → NTP, NTP → LTC and AUTO
- Stratum 1 NTP server (v1–v4) with LTC as the reference
- Balanced digital LTC input on XLR, polarity free
- Automatic format detection from 23.976 to 30 fps, drop frame included
- Digital LTC output on XLR, with input pass-through
- Power over Ethernet (IEEE 802.3af) or 5 V DC
- Works on an isolated network: no Internet, GPS or router
- Set up from a web browser or the OLED display and three buttons
- 60 s holdover, watchdogs and firmware updates with automatic rollback
You already have an LTC timecode running on a cable, but many devices — wall clocks, computers, servers, recorders — cannot read it. They can, however, ask for the time over the network. The converter listens to your LTC and, when a clock or a PC asks “what time is it?”, it answers with the time from the LTC. Nothing else is needed.
The real problem: in studios and control rooms, timecode and network time live in two separate worlds. This converter links them in both directions, so NTP clocks, PCs and legacy LTC equipment all show the same time. Elettronica Mangione has been synchronizing TV studios since 1984.
Three operating modes
- LTC → NTP: the input LTC becomes network time. The converter is a stratum 1 NTP
server with reference ID
LTC. With pass-through on, it also re-generates the LTC on the output to feed a second device. - NTP → LTC: the time from an NTP server becomes a continuous LTC on the output. The
output stays silent until a valid time is known, so a downstream device never receives a false
00:00:00:00. - AUTO: uses the input LTC while it is present and locked, otherwise network time. Switching has hysteresis (5 s of lock, at least 30 s between changes) and the output never stops.
Safe by design
If the LTC is missing for more than 60 seconds, the server tells clients it does not know the time (LI = 3, stratum 16): clients ignore it rather than take a wrong time, and the service resumes by itself when the signal returns. The converter never invents a time.
Date and time zone
LTC carries the time of day but usually neither the date nor the time zone, while NTP always speaks UTC. You enter once how many minutes your LTC is ahead of UTC, and today's date: the converter then advances the date by itself at midnight and remembers it after a power loss. If the LTC carries date and zone in its user bits (SMPTE 309M), the Status page shows them.
Signal Interfaces
- Balanced LTC input: XLR female, digital input, polarity free
- Unbalanced BNC: LTC input or output, selected by a board link
- LTC output: digital output on XLR male
- Network and power: 10/100 Ethernet RJ45 with PoE, or 5 V DC
OLED display and buttons
The display rotates through address and mode, input timecode, NTP server state and alarms. With the three buttons you open the settings and change mode, UTC offset, date and IP address, with no computer and no network.
Web interface
Every setting is available from a web browser, on a PC, tablet or phone. The Status page shows input and output timecode, NTP server state, network and alarms in real time; the Mode page selects the source in one click.
Specifications
NTP LTC Converter
Connectors
- 10/100 Ethernet RJ45 with PoE
- 3-pin female XLR: balanced LTC input
- BNC: unbalanced LTC input or output (selected by a board link)
- 3-pin male XLR: LTC output
- 5 VDC input (when PoE is not used)
LTC input
- Bi-phase mark, balanced digital input
- Polarity free (pins 2 and 3 can be swapped)
- Formats detected automatically: 23.976, 24, 25, 29.97 DF, 29.97 NDF, 30 fps
- Reads date and time zone from SMPTE 309M user bits (display only)
LTC output
- Digital output generated in software, AC coupled
- Level about 2 Vpp balanced (calculated, into 600 Ω)
- Rise time about 25 µs, per SMPTE 12M
- Unbalanced version on BNC, selected by a board link
- Active in NTP → LTC and AUTO, or as pass-through in LTC → NTP
- Silent until a valid time is available
- Not galvanically isolated
NTP server
- UDP port 123, NTP v1–v4 (answered in the client's version)
- Stratum 1, reference ID
LTC - LI 0 when valid, LI 3 / stratum 16 when unsynchronized
- 60 s holdover on the internal crystal
- Per-client rate limit, unicast only
NTP client
- SNTP, up to two servers (NTP → LTC and AUTO modes)
- Sync interval from 60 s to 24 h
- 33 time zones with their own daylight-saving rules
Time zone and accuracy
- Fixed UTC offset from −720 to +840 minutes
- Fine offset up to ±2 s, in microseconds
- Conversion error well below one frame (about 0.2 ms measured on the bench)
- A few milliseconds at the client on a wired network
Network Configuration
- DHCP or fixed address; without DHCP: 192.168.1.100/24
- mDNS name: http://ntpltc-<n>.local
- Web interface over http, port 80
- Optional administrator password
Display and controls
- OLED 128×32, 4 lines of 21 characters
- UP, DOWN, OK buttons with settings menu
- Network address recovery from the buttons
- Status LED
Power supply
- PoE IEEE 802.3af, or 5 VDC
- Power consumption < 5 W
Reliability
- Hardware and software watchdogs
- Protection against restart loops
- Web firmware update with automatic rollback
Hardware Platform
- Processor: 240 MHz dual-core ESP32 with PoE Ethernet
- Dedicated digital LTC input and output
- Firmware 3.1.5
Operating parameters
- Temperature: 0° to 55°
- Humidity: up to 80% (non-condensing)
Physical Characteristics
- Black aluminium desktop enclosure
- Dimensions 8 w x 4.5 h x 12.6 d cm (3.15 w x 1.77 h x 4.96 d inches)
- Weight: 0.5 kg (1.10 pounds)
Compliance
- ROHS, CE
Frequently asked questions
Frequently Asked Questions (FAQ)
If your question is not here, send it to us directly: the people who design the product will answer.
What exactly does the NTP/LTC converter do?
It works both ways. In LTC → NTP mode it reads the LTC timecode you already have and answers clocks, PCs and servers on the network as a stratum 1 NTP server. In NTP → LTC mode it takes the time from an NTP server and generates a continuous LTC signal. In AUTO mode it uses the input LTC while it is present and locked, otherwise network time, and the LTC output never stops.
Do I need Internet or a router?
No. In LTC → NTP mode the time comes from the LTC: all you need is a network between the converter and the clocks, even an isolated one with fixed addresses. Without Internet you set the date once, and the converter then advances it by itself at midnight.
What happens if the input LTC disappears?
For 60 seconds the converter keeps serving time on its own crystal (holdover). It then tells clients it is unsynchronized (LI = 3, stratum 16), so they ignore it rather than take a wrong time. When the LTC returns and locks, the server resumes by itself.
My LTC carries local time: what should I set?
NTP always speaks UTC. On the Time page you enter how many minutes your LTC is ahead of UTC: 0 if the LTC is UTC, 60 for Central Europe in winter, 120 in summer, 240 for Dubai. The offset is fixed: where daylight saving applies, change it by hand when the clocks change.
How accurate is it?
The converter's own conversion error is well below one video frame: about 0.2 ms measured on the bench across the whole chain. On a small wired network a client typically sees a few milliseconds of error. The server is only as accurate as the LTC source it listens to.
Which LTC formats does it recognise?
All six common formats, detected automatically at the input: 23.976, 24, 25, 29.97 drop frame, 29.97 non-drop and 30 fps. The LTC output format is selected on the Mode page.
How is it powered and configured?
It is powered over Ethernet (PoE, IEEE 802.3af) or from 5 V DC. It is configured from any web browser: with a DHCP server it gets its address automatically, without one it uses 192.168.1.100. The main settings can also be changed on the OLED display with the three buttons, including recovering the network address.
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