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Printer Client Instructions

Last updated: 5 January 2026

Legal Entity: OuViTel™ is a trademark of Urimata Ltda., São Paulo, Brazil.
OuViTel Interface in Action

1. Security & Encryption

End-to-End Encryption (E2EE)

All print jobs are encrypted on the sender's side before transmission. Only your printer can decrypt and process the print job. OuViTel™ acts solely as a secure transport layer and does not require access to encryption keys.

What OuViTel™ Can See

OuViTel™ processes limited technical metadata only, such as:

  • Job identifiers
  • Printer connection status
  • Job size (for usage limits and billing)
  • Timestamps and delivery status (success/failure)

Key Ownership & Control

  • Encryption keys are never transmitted to OuViTel™
  • Keys are not persistently stored on OuViTel servers
  • Key generation and handling occur entirely within your environment
  • If you lose access to your printer or encryption keys, encrypted print data cannot be recovered by OuViTel™

Compliance & Security Model

This model supports LGPD (Brazil), GDPR (EU), and privacy-by-design principles.

Service Availability

E2EE protects content only; service availability is governed by your selected plan:

  • Best Effort License: No uptime guarantees, service provided on a reasonable effort basis.
  • Premium License: 99.50% monthly uptime SLA with service credits for failures.

2. Self-Healing Architecture

Automatic Recovery Features

Feature Behavior Benefit
Connection Loss Reconnects every 30s with exponential backoff Survives network outages
Queue Management Stores 50 (Basic) / 500 (Premium) jobs locally No data loss during downtime
Crash Recovery Restores pending jobs after restart Zero manual intervention
Token Validation Auto-renews expired tokens via API Continuous operation

Diagnostic Monitoring

Real-time status reporting:

  • Paper availability
  • USB connectivity
  • Network reachability

Alerts sent to dashboard when issues detected.

3. Webhook Integration

Supported Events

Event Payload Example Use Case
print.success {jobId, timestamp} Update order status in ERP
print.failure {jobId, error: "paper_jam"} Trigger maintenance workflow
printer.offline {lastSeen, issues} Alert IT team
printer.online {timestamp} Resume automated workflows

Security Requirements

POST https://your-webhook-url.com/print-events
Headers:
  X-Ouvitel-Signature: HMAC_SHA256(payload, your_secret)
  X-Timestamp: 1704067200000
Body:
  {"event":"print.success","payload":{...}}

4. Problem Resolution Guide

Common Issues & Fixes

Symptom Likely Cause Solution
"Printer Offline" in dashboard Client not running 1. Check Windows Task Manager
2. Restart printer-client.exe
Print jobs stuck in queue USB communication error 1. Reconnect printer USB
2. Restart client
"Invalid token" errors Token changed in dashboard Reinstall client with new token
Webhooks not delivered Firewall blocking outbound Whitelist ouvitel-zk-production.up.railway.app:443

Advanced Diagnostics

  • Log location: %APPDATA%\OuViTel\logs\
  • Verbose mode: Start client with --debug flag
  • Manual heartbeat: curl -X POST http://localhost:8080/heartbeat

5. Critical Configuration Requirements

Network Setup

Outbound access required:

  • api.ouvitel.com:443 (API communication)
  • webhooks.ouvitel.com:443 (webhook delivery)

Local port: Client uses localhost:8080 for health checks.

System Requirements

Component Minimum Recommended
OS Windows 10 Windows 11 / Server 2022
RAM 512 MB 1 GB
Disk 100 MB free SSD recommended
Printer USB-connected ESC/POS Network printer via CUPS

6. Installation & Maintenance

Initial Setup

  1. Download printer-client.exe from dashboard
  2. Run as Administrator (required for USB access)
  3. Enter your Printer Token (found in dashboard)
  4. Select target printer from list

Updates

  • Automatic: Client self-updates silently during idle periods
  • Manual: Redownload from dashboard if issues persist
  • Version check: printer-client.exe --version

7. Compliance & Data Handling

What We Never Store

  • Print job content (encrypted end-to-end)
  • Document metadata (filename, user, etc.)
  • Local network details

What We Do Store

  • Encrypted job metadata (size, timestamp)
  • Diagnostic status (online/offline, paper status)
  • License information

Data Retention

  • Diagnostic data: 30 days
  • Job metadata: 90 days
  • License records: Duration of contract + 1 year

8. Pro Tips for Reliability

  1. Dedicated Machine: Run client on a machine that's always powered on
  2. USB Best Practices:
    • Use shielded USB cables (<2m)
    • Avoid USB hubs (connect directly to PC)
  3. Firewall Rules: Allow outbound HTTPS to OuViTel domains
  4. Monitoring: Set up uptime checks on http://localhost:8080/health

9. Contact

Urimata Ltda.

São Paulo – Brazil

Email: support@ouvitel.com