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Serial Multiservice Interface Module Overview
CTP bundles are supported on the Serial Multiservice Interface module. CTP bundles on Multiservice Interface modules can operate with the following modes:
Audio—Provides single and dual channel audio support for varying quality audio from 8-bit, 8-KHz quality to 8-bit up to 16-bit, 48-KHz quality (CD quality).
4WTO—Provides single and dual channel audio support for 8-bit, 8-KHz quality with squelch support for radio backhaul. In 4WTO mode, the Multiservice Interface module is interoperable with 4WTO daughter cards.
IRIG—Enables an interrange instrumentation group time code (IRIG-B) signal to be transported through an IP network.
TDC—Provides combined time-correlated support for IRIG/NRZ data for telemetry applications.
Audio Mode
Audio mode provides a high-quality audio (CD quality) interface. Audio mode supports the following features:
One or two simultaneous channels.
Codec sampling rates up to 48 KHz.
Optional μ-law encoding and decoding.
Embedded frame requiring no additional bandwidth.
Configurable output level from 0x to 2x.
Signaling capability with talk squelch.
Figure 1 shows the cable pinouts and the data flow when the Multiservice Interface module operates in audio mode.
4WTO Mode
The CTP 4-wire trunk only (4WTO) analog option provides encoding for one or two analog voice channels into a single CTP IP data stream.
4WTO mode supports the following features:
One or two simultaneous channels.
Codec sampling rate of 8 KHz.
Optional μ-law encoding.
Signaling capability with talk squelch.
Configurable output level from 0x to 2x.
Interoperability with a 4WTO daughter card. Interoperability is supported only on daughter cards that have firmware revision 4 or later. You enable interoperability in the 4WTO daughter card configuration by setting MS interwork to enabled.
IRIG Mode
The Multiservice Interface module enables an interrange instrumentation group time code (IRIG-B) signal to be transported through an IP network. The IRIG-B standard consists of a family of rate-scaled serial time codes with formats containing up to three coded expressions or words. The IRIG-B pulse code contains one frame of 100 elements per second for the time of the year and GPS receiver status. IRIG-B encodes day of year, hour, minute, and second data on a 1-KHz carrier frequency, with an update rate of once per second.
IRIG-B mode supports the following features:
IRIG-B transported at rates between 1 Kbps and 25.5 Kbps.
Configurable output level from 0 to 7.85 volts peak-to-peak based on a 50-ohm termination.
TDC Mode
Time domain correlation (TDC) mode supports special applications in which digital data (NRZ) needs to be closely time correlated with a timing signal (IRIG-B). In TDC mode, the IRIG-B signal is transported on an 8-KHz audio path, and the NRZ data is transported using RTS/DTR (NRZ input) and CTS/DSR (NRZ output). Circuitry on the Multiservice Interface module accepts these two streams and combines them into a single digital data stream that is carried through the IP network in one direction, while making sure that the time relationship between the two signals is closely maintained.
Here is a list of the features of the TDC transport function:
IRIG-B transported at 8-KHz with 16-bit samples; that is, no companding.
NRZ data rates supported from 0.5 KHz to 5000 KHz in 0.5 KHz steps.
Embedded frame requiring no additional bandwidth.
Configurable IRIG-B output level from 0x to 2x.
Figure 2 shows the cable pinouts and the data flow when the Multiservice Interface module operates in TDC mode.
