Digital Audio Buffering; P25 Encryption; Table 20 Inbound P25 Encryption Rules; Table 21 Outbound P25 Encryption Rules - Futurecom P25 Installation & Programming Manual

Digital Audio Buffering

Audio buffering is supported by the DVRS in order to eliminate loss of messages / parts
of messages due to the inherent delays associated with acquiring system access. The
Digital Audio Buffer in the DVR is programmable up to 1800ms.

P25 Encryption

The DVRS transparently passes the P25 encrypted voice used by the subscriber and fixed
network equipment. Even though the DVRS can be programmed to support TG
translation, it cannot support encryption key translation.
When the DVR is on a P25 Digital channel, inbound digital audio from a Local PSU is
handled according to the following table:
Local PSU Call
P25 Clear
P25 Encrypted

Table 20 Inbound P25 Encryption Rules

While the DVR is on a digital channel, outbound digital audio originating from the FNE is
handled according to the following table:
Call from FNE
P25 Clear
P25 Encrypted

Table 21 Outbound P25 Encryption Rules

While the DVR is on a digital channel, outbound digital audio originating from the MSU is
handled according to the following table:
MSU Mode
Digital P25
Digital P25

Table 22 MSU MIC PTT P25 Encryption Rules

The MSU interfaced to the DVR will unmute to inbound or outbound encrypted P25 calls
ONLY if the MSU contains the key used for encryption in its encryption key list.
January 2019
DVRS Installation & Programming Guide – PART II
MSU Secure
Strapping
Clear or Secure
Clear or Secure
MSU Secure Strapping
Clear or Secure
Clear or Secure
MSU Secure Strapping
Clear
Secure
Receiving Local
PSUs
P25 Clear
P25 Encrypted
Receiving Local PSUs
P25 Clear
P25 Encrypted
Receiving Local PSUs
P25 Clear
P25 Encrypted
8M083X25 R14
APX Series P25 Interface
Receiving FNE
P25 Clear
P25 Encrypted
Page 109 of 153