ESChat P25 ISSI Advanced LMR Integration




ESChat / P25 Radio Integration via ISSI


Full Featured LTE to P25 Integration via ISSI


P25 Interoperability via ISSI
ESChat is pleased to offer its Inter-RF Subsystem Interface (ISSI) Gateway that provides TIA-standardized network-level communication between ESChat and Project 25 (P25) radio systems. This ISSI interface was created to facilitate interoperable communication between P25 networks in local and remote neighbor regions. ISSI creates a “network of networks” and is used when first responders and public safety professionals converge on a common location to provide mutual aid.

ESChat’s ISSI Gateway allows ESChat users to communicate with P25 LMR users in Private, Group and Emergency Group Calls. Purposefully built PTT phones, like the Sonim XP7 have a dedicated ‘Red’ Emergency Button that is used to trigger the P25 Emergency Group call.

The ESChat ISSI Gateway supports all P25 voice CODECS, including; AMBE+2™ full-rate (7200 bps), AMBE+2™ enhanced half-rate (3600 bps) and legacy support for IMBE. ESChat has an advanced Priority and Preemption scheme that is fully compatible with the P25 networks. Three modes of preemption are supported, including:

  • User over User (In-Call Talker Override)
  • User over Group
  • Group over Group

The ESChat ISSI Gateway is available “As a Service” for ESChat Cloud based customers, or it can be installed on-site for those operating ESChat Customer Hosted servers.



Logical view of P25 Unit ID to ESChat User Associations





Demonstration Video :: LTE to P25 Interoperability via ISSI