Preliminary Information
Pin Description (continued)
Pin #
5
Name
Rin
Description
MT9122
Receive PCM Signal Input (Input).
128 kbit/s to 4096 kbit/s serial PCM input stream. Data
may be in either companded or 2’s complement linear format. Two PCM channels are time-
multiplexed on this pin. These are the Receive Input reference channels for Echo Cancellers
A and B. Data bits are clocked in following SSI or ST-BUS timing requirements.
Send PCM Signal Input (Input).
128 kbit/s to 4096 kbit/s serial PCM input stream. Data
may be in either companded or 2’s complement linear format. Two PCM channels are time-
multiplexed on this pin. These are the Send Input channels (after echo path) for Echo
Cancellers A and B. Data bits are clocked in following SSI or ST-BUS timing requirements.
Digital Ground:
Nominally 0 volts.
Master Clock (Input):
Nominal 20 MHz Master Clock input. May be connected to an
asynchronous (relative to frame signal) clock source.
Internal Connection (Input):
Must be tied to Vss.
Non-Linear Processor Control (Input):
Controllerless Mode: An active high enables the Non-Linear Processors in Echo Cancellers A
and B. Both NLP’s are disabled when low. Intended for conformance testing to G.165 and it is
usually tied to Vdd for normal operation.
Controller Mode: This pin is ignored (tie to Vdd or Vss). The non-linear processor operation is
controlled by the NLPDis bit in Control Register 2. Refer to the Register Summary.
6
Sin
7
8
9
10
VSS
MCLK
IC
NLP
11
REV
Reversal Detection (Input):
Controllerless Mode: An active high configures all the tone detectors to trigger only when a
2100Hz disable tone with periodic phase reversal is present (per G.165). When low, the tone
detectors will trigger upon detection of any 2100Hz disable tone, with or without periodic
phase reversal (per G.164).
Controller Mode: This pin is ignored (tie to VDD or VSS). The operation is controlled by the
PHDis bit in Control Register 2. Refer to the Register Summary.
12
LAW
A/µ Law Select (Input):
An active low selects
µ−Law
companded PCM. When high, selects A-Law companded PCM.
This control is for both echo cancellers and is valid for both controller and controllerless
modes.
13
FORMAT ITU-T/Sign Mag (Input):
An active low selects sign-magnitude PCM code. When high, selects ITU-T (G.711) PCM
code. This control is for both echo cancellers and is valid for both controller and controllerless
modes.
PWRDN Power-down (Input):
An active low resets the device and puts the MT9122 into a low-power
stand-by mode.
TD2
Tone Detect 2 (Output):
An active low output occurs when Echo Canceller B detects the presence of a valid 2100Hz
disabling tone (G.164 or G.165) on Rin or Sin pins. This output returns to a logic high once the
release criteria are met. The behavior of this pin is identical in both controller and
controllerless modes.
Tone Detect 1 (Output):
An active low output occurs when Echo Canceller A detects the presence of a valid 2100Hz
disabling tone (G.164 or G.165) on Rin or Sin pins. This output returns to a logic high once the
release criteria are met. The behavior of this pin is identical in both controller and
controllerless modes.
14
15
16
TD1
8-19
MITEL [ MITEL NETWORKS CORPORATION ]
