RCV56HCF PCI/CardBus Modem Designer’s Guide
Table 3-4.  MDP Signal Definitions (Cont'd)
| Label | I/O Type | Signal Name/Description | 
| 
 | TELEPHONE LINE/TELEPHONE/AUDIO INTERFACE SIGNALS AND REFERENCE VOLTAGE | |
| TXA1_L1 | O(DF) | Transmit Analog 1 and 2. The TXA1_L1 and TXA2_L1 outputs are differential outputs 180 degrees out of | 
| TXA2_L1 | 
 | phase with each other. Each output can drive a 300 Ω load. | 
| RXA_L1 | I(DA) | Receive Analog. RXA_L1 is a  | 
| 
 | 
 | external hybrid circuit. The input impedance is > 70k Ω. | 
| TELOUT_L1 | O(DF) | Telephone Handset Analog Output. TELOUT_L1 is a  | 
| 
 | 
 | speaker interface circuit. TELOUT_L1 can drive a 300 Ω load. | 
| TELIN_L1 | I(DA) | Telephone Handset Analog Input. TELIN_L1 is a  | 
| 
 | 
 | microphone interface circuit. The input impedance is > 70k Ω. | 
| 
 | 
 | 
 | 
| MIC_M | I(DA) | Modem Microphone Input. MIC_M is a  | 
| MIC_V | I(DA) | Voice Microphone Input. MIC_V is a  | 
| SPKROUT_M | O(DF) | Modem Speaker Analog Output. The SPKROUT_M analog output reflects the received analog input signal. | 
| 
 | 
 | The SPKROUT_M on/off and three levels of attenuation are controlled by bits in DSP RAM. When the speaker | 
| 
 | 
 | is turned off, the SPKROUT_M output is clamped to the voltage at the VC_L1 pin. The SPKROUT_M output | 
| 
 | 
 | can drive an impedance as low as 300 ohms. In a typical application, the SPKROUT_M output is an input to | 
| 
 | 
 | an external LM386 audio power amplifier. | 
| VREF | REF | High Voltage Reference. Connect to VC_L1 through 10 µF (polarized, + terminal to VREF) and 0.1 µF | 
| 
 | 
 | (ceramic) in parallel. | 
| VC_L1 | REF | Low Voltage Reference. Connect to analog ground through 10 µF (polarized, + terminal to VC_L1) and | 
| 
 | 
 | 0.1 µF (ceramic) in parallel. | 
| 
 | 
 | 
 | 
| PLLVDD | PLL | PLLVDD Connection. Connect to VAA and to AGND through 0.1 μF. | 
| PLLGND | PLL | PLLGND Connection. Connect to AGND. | 
| MK4, MK5 | IA | PLL Circuit Strap Option. Connect MK4 to digital ground and leave MK5 open in order to enable the internal | 
| 
 | 
 | PLL circuit. | 
| SPKMD | OA | Modem Speaker Digital Output. The SPKMD digital output reflects the received analog input signal digitized | 
| 
 | 
 | to TTL high or low level by an internal comparator to create a PC Card  | 
| ROCKWELL PROPRIETARY INFORMATION | 1129 | 
