Overvis Connect Protocol Documentation

Overvis Connect Protocol Documentation

https://www.overvis.com/docs/en/overvis-connect/

2026-04-06

Table of Contents

1. 1. Overvis Connect Protocol
2. 2. Basic Protocol
3. 3. EXT0001: Device Parameters
4. 4. EXT0002: Device State
5. 5. EXT0003: Device Journal
6. 6. EXT0004: Device Clock
7. 7. EXT0005: Firmware Update
8. 8. EXT0006: Basic Events
9. 9. EXT0007: Sensitive Information Check
10. 10. EXT0008: Get Device ID
11. 11. EXT0009: DH Key Exchange
12. 12. EXT000A: Device Reboot
13. 13. EXT000B: Next Reconnect
14. 14. EXT000C: Shared Secret Authentication
15. 15. EXT000D: Wrapped Packet
16. 16. EXT000E: Encrypted AES-256-CBC
17. 17. EXT000F: Asynchronous Result
18. 18. EXT0010: Encrypted Gamma
19. 19. EXT0011: EdDSA Authentication
20. 20. EXT0013: File System Read
21. 21. EXT0014: File System Navigate
22. 22. EXT0015: File System Write
23. 23. EXT0016: File System Manage

Overvis Connect Protocol Documentation

Overvis Connect Protocol Overvis Connect is a lightweight communication protocol between device and application. The underlying protocol describes connection support and sending meta information. Additional functionality, such as working with device parameters, reading the device journal, working with the device’s internal clock, etc., is described in the protocol extensions. Complete Documentation Available View all documentation on a single page – Perfect for printing or offline reading Key Features Client-Server Architecture: Device acts as server, application as client Extensible Design: Core protocol with modular extensions Lightweight: Minimal overhead for embedded systems Backward Connectivity: Supports device-initiated connections for NAT/firewall traversal Common Use Cases Communication between embedded devices and cloud platforms Industrial controller data exchange IoT device parameter management Secure device authentication and data encryption Documentation Core Protocol Basic Protocol – Handshake, Keep Alive, request/response format Extensions Device Operations EXT0001: Device Parameters – Read/write device settings EXT0002: Device State – Read current state values EXT0003: Device Journal – Read/clear data history EXT0004: Device Clock – Get/set device time EXT0005: Firmware Update – Firmware management EXT0006: Basic Events – Event management EXT0008: Get Device ID – Unique device identifier EXT000A: Device Reboot – Reboot on disconnect EXT000B: Next Reconnect – Set reconnection parameters Security & Authentication EXT0007: Sensitive Info Check – Value validation EXT0009: DH Key Exchange – Diffie-Hellman key exchange EXT000C: Shared Secret Auth – Authentication with shared secret EXT0011: EdDSA Auth – EdDSA authentication Data Transfer & Encryption EXT000D: Wrapped Packet – Protocol tunneling EXT000E: Encrypted AES-256-CBC – AES encryption EXT0010: Encrypted Gamma – Gamma encryption EXT000F: Async Result – Async process results File System EXT0013: File System Read – Read files EXT0014: File System Navigate – Directory navigation EXT0015: File System Write – Write files EXT0016: File System Manage – File management Document Statuses Status Description Draft Not ready for discussion Discussion Under discussion, pending edits Testing Under implementation, devices not yet for sale Approved Ready, no edits possible, devices on sale Outdated No longer used, kept for reference Support Knowledge Base: Browse this documentation for detailed guides and references Support Center: Visit our Support Center for FAQs and troubleshooting Report an Issue: Submit a support ticket for technical assistance

Overvis Connect Protocol Documentation

Basic Protocol Document status: Approved (2020-02-01) Data Exchange Procedure Overvis Connect is a client-server protocol. The device is always the server, the application is the client. The client sends requests, the server responds. The connection initiator can be either party. When the server (device) initiates a connection, it’s called “backward” connection—useful for bypassing firewalls when multiple devices connect to one cloud application. Usually, the first request is 0000 Handshake to get device type/version and supported extensions. If there’s no exchange for a period, the server terminates the connection. To prevent this, the client must regularly send 0001 Keep Alive or other commands. The timeout is transmitted in the Handshake response (KA field). The server must respond within 10 seconds, otherwise the client may terminate or repeat the request. Request and Response Format <TID> <PID> <LEN> <CMD> <DATA> Fields are coded Big Endian (most significant byte first). Field Length Description TID 2 bytes Transaction number PID 2 bytes Protocol ID, always 0x3900 LEN 2 bytes Package length (excluding TID, PID, LEN) CMD 2 bytes Command code DATA LEN - 2 Data field Maximum packet length is 65535 bytes, but devices may set smaller limits via FLIM field in Handshake response. Error Response <TID> 3900 0004 <ECMD> <ERROR> Where ECMD is the command code with MSB set (<CMD> + 0x8000) and ERROR is 2-byte error code. Common Error Codes Code Description 0001 Unknown error 0002 Device I/O error 0003 Device busy (try again later) 0004 Invalid LEN field 0005 Unknown command 0006 Invalid DATA field 0007 No access rights Commands 0000 Handshake Request meta-information about the device. Request: <TID> 3900 0002 0000 Response: <TID> 3900 <LEN> 0000 <IC> <HW> <FW> <FLIM> <KA> [<EXT> ...] Field Length Description IC 2 bytes Device type category (manufacturer ID) HW 2 bytes Hardware type (LSB decimal = AO version) FW 4 bytes Firmware version (MSB 2 bytes = version type) FLIM 2 bytes Max packet length in bytes KA 2 bytes Keep-alive timeout in seconds EXT 2 bytes Supported extension codes (0 or more) 0001 Keep Alive Maintain connection when no other requests are needed. Request: <TID> 3900 0002 0001 Response: <TID> 3900 0002 0001

Overvis Connect Protocol Documentation

EXT0001: Device Parameters Extension dependencies: none Document status: Approved (2020-02-01) This extension describes reading and setting device parameters (setpoints/settings). Parameters are stored in persistent memory. To optimize work with many records and eliminate intermediate states, the extension supports transactions—changes are saved in RAM first, then written to permanent memory when the transaction completes. Commands 0002 Read Parameters Read a block of parameters from persistent memory. Request: <TID> 3900 <LEN> 0002 <SOURCE> [( <OFFSET> <BLOCKLEN> ) ...] If OFFSET and BLOCKLEN are not specified, returns maximum data without offset. Multiple pairs can be specified for multiple blocks in response. Response: <TID> 3900 <LEN> 0002 (<BLOCKDATA>) ... Field Length Description SOURCE 1 byte Data source OFFSET 2 bytes Offset in parameter structure BLOCKLEN 2 bytes Block length BLOCKDATA BLOCKLEN Parameter block bytes Errors: Code Description 0010 Incorrect SOURCE 0011 Reading out of bounds 0012 Response overflow 0013 ROM read error 0003 Write Parameters Write parameters and manage transactions. When initialized, the device allocates RAM for the parameter structure and copies from permanent memory. Changes accumulate in RAM. Device keeps the structure for at least 10 seconds. On transaction completion (TRCON = 2), changes are written to permanent memory. Request: <TID> 3900 <LEN> 0003 <SOURCE> <TRCON> [( <OFFSET> <BLOCKLEN> <BLOCKDATA> ) ...] Response: <TID> 3900 0002 0003 Field Length Description SOURCE 1 byte Data source TRCON 1 byte Transaction control: 0=start new, 1=continue, 2=commit OFFSET 2 bytes Offset in parameter structure BLOCKLEN 2 bytes Block length BLOCKDATA BLOCKLEN Parameter block bytes Errors: Code Description 0010 Incorrect SOURCE 0011 Writing out of bounds 0012 ROM write error 0013 ROM resource expired 0014 RAM error (can’t allocate) 0015 Transaction aborted by another connection 0016 Transaction timeout 0017 Attempting to continue completed transaction

Overvis Connect Protocol Documentation

EXT0002: Device State Extension dependencies: none Document status: Approved (2020-02-01) This extension describes reading the current values of device status parameters. Commands 0004 Read State Read a block of device state parameter values. Request: <TID> 3900 <LEN> 0004 [( <OFFSET> <BLOCKLEN> ) ...] If OFFSET and BLOCKLEN are not specified, returns maximum data. Multiple pairs can be specified for multiple blocks. Response: <TID> 3900 <LEN> 0004 (<BLOCKDATA>) ... Field Length Description OFFSET 2 bytes Offset in parameter structure BLOCKLEN 2 bytes Block length BLOCKDATA BLOCKLEN Parameter block bytes Errors: Code Description 0010 Reading out of bounds 0011 Response overflow

Overvis Connect Protocol Documentation

EXT0003: Device Journal Extension dependencies: EXT000F Document status: Testing This extension describes reading and clearing the journal of accumulated data (typically measurement history). Journal Format <DATE> (<VAL> ...) Field Length Description DATE 4 bytes Unix timestamp (seconds since 1970-01-01 UTC) VAL variable Tracked parameter values (device-specific) All journal entries have the same length within a session. Commands 0005 Read Journal Read tracked parameter values. Returns maximum records that fit in response. Request: <TID> 3900 0006 0005 <AFTERREC> Response: <TID> 3900 <LEN> 0005 <LASTREC> [<RECORDS>] Field Length Description AFTERREC 4 bytes LASTREC from previous packet (0 for first request) LASTREC 4 bytes Address of last entry in current packet RECORDS variable Journal entries (descending date order) Errors: Code Description 0010 ROM read error 0011 Invalid AFTERREC 0006 Clear Journal Clear all journal contents. Starts asynchronous process (use 0019 for result). Request: <TID> 3900 0002 0006 Response: <TID> 3900 <LEN> 0006 <PROCID> [<BUSYTIME>] Field Length Description PROCID 2 bytes Process ID for result query BUSYTIME 4 bytes Max time if not background Process Errors: Code Description 0010 ROM write error 0011 ROM resource expired

Overvis Connect Protocol Documentation

EXT0004: Device Clock Extension dependencies: none Document status: Testing This extension describes reading and changing the device’s internal clock time. Commands 0007 Get Time Read current device time in UTC. Request: <TID> 3900 0002 0007 Response: <TID> 3900 0006 0007 <DTIME> Field Length Description DTIME 4 bytes Unix timestamp (seconds since 1970-01-01 UTC) Errors: Code Description 0010 Time reading error 0008 Set Time Set new device time. Request: <TID> 3900 0006 0008 <STIME> Response: <TID> 3900 0006 0008 <DTIME> Field Length Description STIME 4 bytes Time to set (Unix timestamp) DTIME 4 bytes Current device time (should equal STIME) Errors: Code Description 0010 Time write error

Overvis Connect Protocol Documentation

EXT0005: Firmware Update Extension dependencies: EXT000F Document status: Approved (2020-02-01) This extension describes the firmware update process. Commands 0009 Get FW File Version Read firmware file version on device. Request: <TID> 3900 0002 0009 Response: <TID> 3900 0006 0009 <FWVER> Field Length Description FWVER 4 bytes FW file version (MSB 2 bytes = version type) Errors: Code Description 0010 ROM read error 0011 FW file not found 000A Delete FW File Delete firmware file. Execute before writing new file. Asynchronous process. Request: <TID> 3900 0002 000A Response: <TID> 3900 <LEN> 000A <PROCID> [<BUSYTIME>] Process Errors: Code Description 0010 ROM error 0011 ROM resource expired 000B Send FW File Write firmware file to device. Request: <TID> 3900 <LEN> 000B <OFFSET> <TOTLEN> <BLOCKDATA> Response: <TID> 3900 0002 000B Field Length Description OFFSET 4 bytes Byte offset in FW file TOTLEN 4 bytes Total FW file length BLOCKDATA variable Data block Errors: Code Description 0010 Out of bounds (TOTLEN) 0011 OFFSET/BLOCKDATA mismatch 0012 ROM write error or data exists 000C Start FW Update Start firmware update. Application should disconnect after response. Request/Response: <TID> 3900 0002 000C Errors: Code Description 0010 ROM read error 0011 FW file not found 0012 FW file CRC error

Overvis Connect Protocol Documentation

EXT0006: Basic Events Extension dependencies: EXT000F Document status: Testing This extension describes reading and management of simple events (scheduled or triggered by parameter changes). Event Format <DATE> (<PARAM> ...) Field Length Description DATE 4 bytes Unix timestamp PARAM regulated Parameter sequences (device-specific) Commands 000D Read Events Request: <TID> 3900 0006 000D <AFTEREV> Response: <TID> 3900 <LEN> 000D <LASTEV> [<EVENT> ...] Field Length Description AFTEREV 4 bytes LASTEV from previous packet (0 for first) LASTEV 4 bytes Address of last entry EVENT regulated Event data Errors: 0010 ROM read error, 0011 Invalid AFTEREV 000E Write Events Request: <TID> 3900 <LEN> 000E (<EVENT> ...) Response: <TID> 3900 0002 000E Errors: 0010 ROM write, 0011 ROM expired, 0012 No space, 0013 Invalid EVENT 000F Delete Events Request: <TID> 3900 <LEN> 000F (<EVENT> ...) Response: <TID> 3900 0002 000F Errors: 0010 ROM write, 0011 ROM expired, 0012 Invalid EVENT 0010 Clear Events Delete all events. Asynchronous process. Request: <TID> 3900 0002 0010 Response: <TID> 3900 <LEN> 0010 <PROCID> [<BUSYTIME>]

Overvis Connect Protocol Documentation

EXT0007: Sensitive Information Check Extension dependencies: none Document status: Approved (2020-02-01) This extension validates a value known to the server for the client (e.g., a password). Returns boolean—valid or not. No device state changes occur. Useful when application and device trust each other but application doesn’t trust user. Example: user proves physical possession of device by entering a code displayed on device. No brute-force protection needed on device side due to state immutability requirement. Commands 0011 Confirm Value Correctness Request: <TID> 3900 <LEN> 0011 <KIND> <VALUE> Response: <TID> 3900 0003 0011 <RESULT> Field Length Description KIND 2 bytes Value type (implementation-specific) VALUE variable Value to check RESULT 1 byte 1=correct, 0=incorrect Errors: Code Description 0010 Invalid KIND

Overvis Connect Protocol Documentation

EXT0008: Get Device ID Extension dependencies: none Document status: Approved (2020-02-01) This extension retrieves the device’s unique 64-bit identifier (UID). Commands 0012 Get Device ID Read unique 64-bit identifier. Can be MAC address (zero-padded) or random number generated during manufacture. Must be unique and immutable; unpredictability not required. Request: <TID> 3900 0002 0012 Response: <TID> 3900 000A 0012 <UID> Field Length Description UID 8 bytes Unique device identifier Errors: Code Description 0010 Error reading UID

Overvis Connect Protocol Documentation

EXT0009: DH Key Exchange Extension dependencies: none Document status: Approved (2020-02-01) Describes exchanging public key parameters using Diffie-Hellman algorithm for establishing encrypted sessions. Reference: Diffie-Hellman key exchange Commands 0013 Public Data for New Shared Secret Exchange parameters and public keys. Can be sent anytime; if during encrypted session, subsequent exchanges use new key. Request: <TID> 3900 <LEN> 0013 <GLEN> <GKEY> <PLEN> <PKEY> <SKEY> Response: <TID> 3900 <LEN> 0013 <DKEY> Field Length Description GLEN 2 bytes Length of GKEY GKEY GLEN Radix g PLEN 2 bytes Length of PKEY PKEY PLEN Module p SKEY variable Server public key A DKEY variable Device public key B Errors: Code Description 0010 GLEN/PLEN too small 0011 GLEN/PLEN too big 0012 Shared secret too short 0013 Shared secret too long 0014 Key exchange calculation error

Overvis Connect Protocol Documentation
EXT000A: Device Reboot Extension dependencies: none Document status: Approved (2020-02-01) Commands 0014 Reboot Device on Disconnect Reboot request at session end. Doesn’t cause immediate reboot—changes connection state so device restarts when disconnected. Request: <TID> 3900 0002 0014 Response: <TID> 3900 0002 0014 No additional errors.

Overvis Connect Protocol Documentation

EXT000B: Next Reconnect Extension dependencies: none Document status: Testing For backward connections only. Sets delay and address for next device connection. Commands 0015 Set Next Reconnect Parameters stored in RAM, reset to defaults on: restart, successful connection, or exceeded attempts. Request: <TID> 3900 <LEN> 0015 <DELAY> [ <PORT> [ <HOST> ]] Response: <TID> 3900 0002 0015 Field Length Description DELAY 4 bytes Delay in ms PORT 2 bytes Server port HOST variable Domain/IP as ASCII Errors: Code Description 0010 Invalid DELAY

Overvis Connect Protocol Documentation

EXT000C: Shared Secret Authentication Extension dependencies: EXT0008 Document status: Approved (2020-02-01) Two-way authentication using 256-bit secret key known to application. Device must have unique UID for application to find its key. Limitation: Application stores all secret keys in clear text. Compromised application list affects all devices; keys cannot be changed on sold devices. See EXT0011 for more secure alternative. Commands 0016 Device-Server Shared Secret Authentication Client generates two random sequences, sends them with hash of first sequence + secret key. Device verifies, responds with hash of second sequence + secret key. For each connection, client is unauthenticated with minimum rights (commands 0000, 0001, 0012, 0016, encryption setup). Request: <TID> 3900 0062 0016 <DTOKEN> <STOKEN> <CHALLENGE> Response: <TID> 3900 0022 0016 <ANSWER> Field Length Description DTOKEN 32 bytes Random 256-bit sequence STOKEN 32 bytes Random 256-bit sequence CHALLENGE 32 bytes First 256 bits of SHA-512(DTOKEN + SKEY) ANSWER 32 bytes First 256 bits of SHA-512(STOKEN + SKEY) Errors: Code Description 0010 Hash mismatch (client auth error) 0011 Too many requests, try later

Overvis Connect Protocol Documentation

EXT000D: Wrapped Packet Extension dependencies: none Document status: Approved (2020-02-01) Wrap any data in Overvis Connect packets. Wrapped packets can exceed session limit—split across multiple commands. Enables tunneling any protocol (HTTP, FTP, etc.). Commands 0017 Exchange Wrapped Packets Long requests split across multiple commands; device responds with OFFSET only until last part. Long responses require multiple commands with OFFSET to retrieve all parts. Request: <TID> 3900 <LEN> 0017 <OFFSET> [ <REMLEN> <BLOCKDATA> ] Field Length Description OFFSET 4 bytes Block offset (or previous response offset for continuation) REMLEN 4 bytes Remaining request length (0=last part) BLOCKDATA variable Data block Response: <TID> 3900 <LEN> 0017 <OFFSET> [ <ESTREM> <BLOCKDATA> ] Field Length Description OFFSET 4 bytes Block offset in response ESTREM 4 bytes Estimated remaining length (0=last part) BLOCKDATA variable Response data Errors: Code Description 0010 Request too long 0011 Invalid OFFSET

Overvis Connect Protocol Documentation

EXT000E: Encrypted AES-256-CBC Extension dependencies: none Document status: Testing Full encryption using AES 256 CBC with single key buffer for requests and responses. Key exchange via other extensions. Commands 0018 Send Encrypted Request Devices supporting this return error 0006 for non-wrapped commands except Handshake, KeepAlive, and encryption setup (e.g., EXT0009). Request/Response: <TID> 3900 <LEN> 0018 <PAYLOAD> PAYLOAD Format <LEN> <CMD> <DATA> <CHKSUM> <PADDING> Field Length Description LEN 2 bytes Length of CMD + DATA CMD 2 bytes Command code DATA variable Data field CHKSUM 2 bytes Byte sum of CMD + DATA PADDING multiple of 16 Random bytes (min 128 total PAYLOAD) Errors Decryption error (unencrypted): <TID> 3900 0004 8018 0010 All other errors are encrypted within PAYLOAD. If client can’t decrypt response, it must terminate connection.

Overvis Connect Protocol Documentation

EXT000F: Asynchronous Result Extension dependencies: none Document status: Approved (2020-02-01) Retrieve results of asynchronous processes started by other commands. Process result persists across reconnections. Commands 0019 Get Asynchronous Process Result Request: <TID> 3900 0004 0019 <PROCID> Response: <TID> 3900 <LEN> 0019 <PERROR> [<EXTRA>] Field Length Description PROCID 2 bytes Process identifier PERROR 2 bytes Error code (0=success) EXTRA variable Additional result data Errors: Code Description 0010 Invalid PROCID 0011 Result not yet available

Overvis Connect Protocol Documentation

EXT0010: Encrypted Gamma Extension dependencies: none Document status: Approved (2020-02-01) Full encryption using Gamma algorithm with single key buffer. Algorithm Uses 40-byte key, encrypts in 16-byte blocks. For each block: Calculate SHA-1 hash of key (use first 16 bytes) After each block, new key = SHA-1 hash (20 bytes) + data block before encryption (16 bytes) + next block number (4 bytes) Block encryption (16 bytes): Permutation: For each byte 0-15 of key hash, split into tetrads (nibbles). Swap high tetrad of data block (at hash high nibble index) with high tetrad of next byte (at hash byte index). Same for low tetrad. XOR: Bitwise XOR of key hash with permutation result. Key for block 0: SHA-1 hash of key #1 (20 bytes) + key #2 (16 bytes) + block number zeros (4 bytes). Decryption reverses: XOR first, then reverse permutation. Commands 0018 Send Encrypted Request Same structure as EXT000E. Devices return error 0006 for non-wrapped commands except Handshake, KeepAlive, and encryption setup. Request/Response: <TID> 3900 <LEN> 0018 <PAYLOAD> PAYLOAD Format <WRAPLEN> <CMD> <DATA> <CHKSUM> <PADDING> Field Length Description WRAPLEN 2 bytes Length of CMD + DATA CMD 2 bytes Command code DATA variable Data field CHKSUM 2 bytes Byte sum of CMD + DATA PADDING multiple of 16 Random bytes (min 128 total) Decryption error returned unencrypted: <TID> 3900 0004 8018 0010

Overvis Connect Protocol Documentation

EXT0011: EdDSA Authentication Extension dependencies: none Document status: Discussion Two-way authentication using EdDSA (Ed25519). Public key length: 32 bytes, signature: 64 bytes. Both public keys known to both parties. Private keys never transferred. Device public key serves as unique identifier. Authentication Process Server sends 001A with its public key and random DCHALLENGE Device verifies server key, responds with its public key and SCHALLENGE Server sends 001B with signature of SCHALLENGE Device responds with signature of DCHALLENGE Unauthenticated clients have minimum rights (0000, 001A, 001B, Keep Alive). Commands 001A Start Authentication Request: <TID> 3900 0042 001A <SPUBKEY> <DCHALLENGE> Response: <TID> 3900 0042 001A <DPUBKEY> <SCHALLENGE> Field Length Description SPUBKEY 32 bytes Server public key DPUBKEY 32 bytes Device public key SCHALLENGE 32 bytes Random bytes for server to sign DCHALLENGE 32 bytes Random bytes for device to sign Errors: 000A Server key mismatch, 000B Too many requests 001B Confirm Authentication Request: <TID> 3900 0042 001B <SSIGN> Response: <TID> 3900 0042 001B <DSIGN> Field Length Description SSIGN 64 bytes Server signature of SCHALLENGE DSIGN 64 bytes Device signature of DCHALLENGE Errors: 000A Invalid signature, 000B Not initialized/timeout, 000C Device busy 001C Create New EdDSA Secret Change server public key and regenerate device key pair. Requires prior authentication. Request/Response: <TID> 3900 0022 001C <SPUBKEY>/<DPUBKEY> Errors: 000A Key generation error

Overvis Connect Protocol Documentation

EXT0013: File System Read Extension dependencies: none Document status: Discussion Commands 001E Access File Get read access. Returns temporary handle, auto-closes after 30 seconds of inactivity. Request: <TID> 3900 <LEN> 001E <FILENAME> Response: <TID> 3900 <LEN> 001E <HANDLE> <FILESIZE> [<FILETIME> <ATTR>] Field Length Description FILENAME variable File path HANDLE 4 bytes Temporary file ID FILESIZE 4 bytes File size FILETIME 4 bytes Last modified time ATTR 2 bytes File attributes Errors: 0010 Read error, 0011 Not found, 0012 No free handles, 0013 Already open 001F Read File Request: <TID> 3900 000C 001F <HANDLE> <OFFSET> <BLOCKLEN> Response: <TID> 3900 <LEN> 001F <BLOCKDATA> Errors: 0010 Read error, 0011 Invalid handle, 0012 Out of bounds

Overvis Connect Protocol Documentation

EXT0014: File System Navigate Extension dependencies: none Document status: Discussion Commands 0020 Access Directory Request: <TID> 3900 <LEN> 0020 <PATH> Response: <TID> 3900 0006 0020 <HANDLE> Errors: 0010 Read error, 0011 Wrong path, 0012 No free handles 0021 Read Directory Contents Request: <TID> 3900 0006 0021 <HANDLE> Response: <TID> 3900 <LEN> 0021 [(<FILESIZE> <FILETIME> <ATTR> <NAMELEN> <NAME>) ...] Field Length Description FILESIZE 4 bytes Size (0 for directories) FILETIME 4 bytes Last modified ATTR 2 bytes Attributes NAMELEN 2 bytes Name length NAME NAMELEN Item name Errors: 0010 Read error, 0011 Invalid handle, 0012 No free handles

Overvis Connect Protocol Documentation

EXT0015: File System Write Extension dependencies: none Document status: Discussion Commands 0022 Access File for Writing Get write access. Creates directories/file if needed. Auto-closes after 30 seconds. Request: <TID> 3900 <LEN> 0022 <FILENAME> Response: <TID> 3900 <LEN> 0022 <HANDLE> <FILESIZE> [<FILETIME> <ATTR>] Errors: 0010 Read error, 0011 Write error, 0012 No handles, 0013 Already open 0023 Write File Request: <TID> 3900 <LEN> 0023 <HANDLE> <OFFSET> <DATA> Response: <TID> 3900 0006 0023 <FILESIZE> Field Length Description HANDLE 4 bytes File handle OFFSET 4 bytes Write position DATA variable Data to write FILESIZE 4 bytes Current file size Errors: 0010 Write error, 0011 Invalid handle, 0012 Invalid offset, 0013 No space

Overvis Connect Protocol Documentation

EXT0016: File System Manage Extension dependencies: EXT0015 Document status: Discussion Uses 32-bit file system element identifiers from other FS extensions. Commands 0024 Rename/Move Element Only for quick operations. Returns 0012 for time-consuming moves (between volumes). Request: <TID> 3900 <LEN> 0024 <HANDLE> <PATH> Response: <TID> 3900 0002 0024 Errors: 0010 Write error, 0011 Invalid handle, 0012 Can’t do synchronously, 0013 Already exists 0025 Remove/Delete Element Closes handle after execution. Returns 0012 for directories with content. Request: <TID> 3900 0006 0025 <HANDLE> Response: <TID> 3900 0002 0025 Errors: 0010 Write error, 0011 Invalid handle, 0012 Can’t do synchronously 0026 Close Access Free handle for other operations. Not required for cache sync. Request: <TID> 3900 0006 0026 <HANDLE> Response: <TID> 3900 0002 0026 Errors: 0010 Invalid handle