E-4 APPENDIX E: TECHNICAL INFORMATIONThe EIA-232 Interface Your modem’s serial port is factory set to signal according to the EIA-232standard. See Figure A-1, Signals at your Business Modem's Serial Port.Wiring a DB-25 toDB-9 CableDB-9 connectors for PCs should be wired at the computer end of thecable as shown below.MinimumRequirementsSome computer/terminal equipment supports only a few of yourmodem’s EIA-232 signals. The minimum required for your modem tooperate asynchronously follows:DB-25 DB-9 Supports this signalPin Pin Function2 3 Transmitted Data3 2 Received Data7 5 Signal Ground20 4 Data Terminal Ready
