User's Manual

Chapter 3 – Electrical Characteristics
Multi-Tech Systems, Inc. SocketModem CDMA Developer’s Guide 9
Chapter 3 – Electrical Characteristics
Electrical characteristics for the 5V Serial SocketModem are presented in this chapter.
I/O Electrical Characteristics
5 Vdc Characteristics (TA = -20° C to 55° C; VDD = 5 V ± 0.25 V) VDDMAX = 5.25 V
Digital Inputs
–DTR (40), –TXD (35), –RTS (33), –RESET (24)
Input High
Min 3.675 V
Input Low
Max 1.4 V
Digital Outputs
–DCD (39), –CTS (38), –DSR (37), –RI (36), –RXD (34)
Output High
Min. 4 V
Output Low
Max 0.4 V
Current
Drive: 2 ma
Digital Input Capacitance 5 PF
Power Consumption
Operating Mode Band Average (mA)
CDMA RXTX Cellular 615
Full Power PCS 770
Cellular 340CMA RXTX
Average Power
PCS 445
Cellular 20
CDMA Standby
PCS 20
Handling Precautions
All devices must be handled with certain precautions to avoid damage due to the accumulation of static
charge. Although input protection circuitry has been incorporated into the devices to minimize the effect of
this static buildup, proper precautions should be taken to avoid exposure to electrostatic discharge during
handling and mounting.