User's Manual

APPLICANT: MOTOROLA, INC. FCC ID: IHDT6AC1
Exhibit 8
45
5.3 Data port considerations.
5.3.1 Data levels.
The D15 data lines are operating in 0 to 5V logic. All the
In/Out signals are bufferd by an MC74VHCT244 buffer.
DTR, DSR, RTS, CTS, DCD lines are "1" (active) in 0V and "0"
(inactive) in 5V.
The signal treshoulds are:
Vih 2.0V min.
Vil 0.8V max.
Voh 4.4V min. @ 50uA or 3.8V min. @ 8mA.
Vol 0.1 max. @ 50uA or 0.44V @ 8mA.
5.3.2 Select the data mode:
The D15 can support two different modes of operation:
SoftGsm - For PC applications.
RS232 full flow control - General applications.
The RS232 is the default mode and no action is needed to
switch to this mode.
The SoftGsm require hardware connection to two lines.
Down link pin should be connected via 22KOhm to ground.
DSC_EN pin should be connected via 22KOhm to ground.