VLT Protocol (HTTP vltdata NRM/BTH)
VLT on HTTP 5246: body field vltdata, type NRM or BTH, 15-digit IMEI, 78-char fix, HTTP 200 or 400.
On Traxelio
What VLT trackers do once they are on Traxelio
Point this protocol at Traxelio
Point VLT at Traxelio
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1
Capture a VLT fingerprint
Confirm an HTTP body whose vltdata starts with NRM or BTH plus a 15-digit IMEI.
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2
Point VLT at 5246
Configure only VLT to HTTP 5246. VLT on 5246 is not VNET on 5205 or Visiontek on 5069.
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3
Wait for HTTP 200
A known IMEI gets HTTP 200. An unknown IMEI gets HTTP 400.
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4
Prove one VLT fix
Send one NRM record with valid flag 1 on 5246 and verify a map point.
Still offline after GPS lock
VLT still not landing
- VLT aimed at the wrong port
VLT on 5246 is not VNET on 5205 or Visiontek on 5069.
- Got HTTP 400 instead of 200
The 15 digits after NRM or BTH are unknown. Bind that IMEI before debugging GPS.
- HTTP 200, empty map
A valid flag of 0 will not plot. Wait for an NRM record whose flag is 1. BTH is history.
FAQ
VLT leftover questions
Does VLT send Concox 0x7878 frames?
No. VLT is HTTP. The body carries a vltdata field that starts with NRM or BTH plus a 15-digit IMEI.
What is the difference between NRM and BTH?
NRM is one 78-character fix after the IMEI. BTH is a 3-digit count followed by that many 78-character history records.
Why does a VLT request succeed without a map fix?
HTTP 200 only means the IMEI is known. A map point needs a record whose valid flag is 1.
What does the H or L letter mean on VLT?
The letter after the 2-digit alert id marks history (H) versus live (L). A later H/M/S letter is the vehicle mode; M is motion.
Can a VLT unit run SMS setup or a controlled-action flow?
This dialect is positions only. The listed device is VLT. There is no SMS family on this row.