MITSUBISHI ELECTRONICS AMERICA, INC.
ST200 Series Technical Support Manual
17
January 2000
line, a power-on signal line, +12V DC power, and ground. The serial data lines transmit keypad
strokes and display commands to/from the transceiver.
The PTT handset must be securely connected to the junction box prior to power-on of the MT.
Net radio operation also requires an external monitoring speaker.
4.10
Other Accessories
Other accessories such as Mitsubishi hands free microphones and external speakers are available
through equipment distributors. Customers should contact these distributors directly concerning
cost and availability.
5.0 Product Operation
Mitsubishi satellite telephones are user friendly, operating like a cellular phone (i.e., no dial tone)
and requiring minimal user interaction. These MTs have many built-in features including special
function keys, user programmability options, and security features. This section includes a brief
design overview as useful background for understanding MT operations.
5.1 Design Overview
The Mitsubishi MTs operate under a blanket license from the FCC for MSAT Service under Part
25 (Satellite Communications) of its rules. This license, on file with the FCC (File No. 2823-
DSE-P/L-93), does not require special MT identification tags for compliance. The fixed site
MT, ST221M, also complies with Part 15 of the FCC Rules as a Class B unintentional source of
radiation subject to the conditions thereunder. The land mobile MT has no requirement for Part
15 compliance.
The MSAT network operates in the L-Band of the frequency spectrum, roughly covering 1.5-1.6
GHz. Because L-Band signals are subject to fading, Mitsubishi MT design includes additional
margin to assure performance and reliability. The terminals’ digital modulation and signal
