Tremol
Tremol is a Bulgarian manufacturer whose ZFP (Zero Frame Protocol) family is distinct from the broader ISL stack used by most other AMEF vendors. e-bon supports two firmware generations side by side: Tremol (legacy ZFP firmware, covering M20, S20, and M-PR series) and Tremol V2 (newer revisions on M-PR2 and S-PR). Both are kept in the registry because some installed-base devices have not been firmware-upgraded; pick the variant that matches the firmware actually running on the unit.
At a glance
| Protocol id | Family | Default TCP port | Default baud | Transports | Probe order |
|---|---|---|---|---|---|
tremol.zfp | zfp | 4999 | 115200 | TCP, Bluetooth, Serial | 4 |
tremol-v2.zfp | zfp | 4999 | 115200 | TCP, Bluetooth, Serial | 5 |
Supported transports
Both Tremol variants accept TCP/IP over wired Ethernet, Bluetooth, and Serial (RS-232). USB-attached units go through a USB-to-Serial bridge (CDC-ACM or FTDI) and are addressed as Serial — there is no native USB transport. Wi-Fi for the AMEF link is not supported; see the Wi-Fi note in Supported devices.
Connection defaults
Tremol's distinguishing feature at the transport level is the default TCP port 4999 — different from the ISL family's 9100. If you point e-bon at a Tremol printer with the wrong port preset you will see a clean refusal at the connect step, not a protocol error. Serial and Bluetooth links negotiate at 115200 baud.
Known quirks / firmware tips
The two-protocol split (tremol.zfp vs tremol-v2.zfp) is the main thing to be aware of. If auto-detect picks the wrong one, the symptom is usually a successful link but malformed responses on the first fiscal command — re-pair against the other variant. There are no other protocol-specific quirks documented at this time; for link-layer issues use the standard Troubleshooting checklist.
Pairing flow
Tremol printers pair through the standard Android flow: choose the transport, accept the suggested protocol when auto-detect lands on either Tremol variant, and confirm a test print. If a Tremol V2 unit is misidentified as legacy Tremol (or the other way round) re-run pairing with the protocol set explicitly. The full pairing walkthrough is in Pairing your fiscal printer.
Next steps
- Supported devices — full compatibility matrix and family overview.
- Pairing your fiscal printer — operational pairing flow on Android.
- Troubleshooting — when a paired device goes offline or refuses to print.