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 the OMACS Core via ISSI. 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 XP8 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