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© MiMOMax 2013 Four Wire Audio
Interface Manual
1.1
H
IGH
S
PEED
S
ERIAL
I
NTERFACE
(HSSI)
The High Speed Serial Interface (HSSI) is a proprietary synchronous serial interface
developed by MiMOMax to
enable Network Interface Box’s to be connected to Radio Units.
The connection allows user and configuration data to pass between the two units. User data
presented to the Radio Unit passes to the remote end and ultimately to the terminating
Network Interface Box.
1.2
A
UDIO
Up to 6 fully independent transmit and receive audio paths (4 wire connections) are provided
with E&M signalling. Two configuration options are provided, one where an E-Lead signal is
required for audio to pass (dynamic), and the other where the selected audio channels are in
an always up configuration (static).
The audio transport is achieved using a G726 32 kbps ADPCM Vo-coder to offer low latency,
tone transparent high quality audio. The operational frequency range is 65 Hz to 3500 Hz.
1.3
D
ATA
A single EIA232 compliant data port is provided at 9600 baud (8N1 no hardware flow control)
for inter-site communications. The UART configuration is set in firmware so a special order is
required for an alternate rate. Note that the UART is disabled in Fixed Channel Mode.
1.4
C
ONFIGURATION
Configuration is provided for by an on board selector switch. Several configuration options are
available including a range of static and dynamic combinations. These are described in
section 2.3.5.
Radio Unit Four Wire Audio Interface Co-Located in the 2U Rack Tray
