| A | B |
| BBL | Basic Business Lines |
| CEN | Centrex |
| VM | Voice Mail |
| BBLVMENH | Basic Business Line Voice Mail Enhanced |
| BBL3Y | Basic Business Line, 3-year contract |
| CEN73-962Y | Centrex, 73-96 lines, 2-year contract |
| CEN73962YB | Centrex, 73-96 lines, 2-year contract, Illinois Zone B |
| SCTXI | Centrex Guidepoint |
| SPOTI | Basic Business Line Guidepoint |
| VMBAS | Standard Voice Mailbox |
| BBL4FP | Basic Business Line 4-option Feature Package |
| Call Forward Busy, Call Forward No Answer | Required Line Features for Voice Mail |
| Call Forward Variable | Optional Line Feature for Voice Mail |
| CENVMBAS | Standard Voice Mailbox on Centrex System |
| SGRPI | Switch classification; Saville guidepoint for Analog Trunks |
| NTAGIN1Y | National Inbound Analog Trunk 1 year contract |
| NTAG2WD1Y | National Two Way Analog Trunk with DID 1 year contract |
| NTFT1ADV1Y | National Fractional Digital T-1 Facility Advanced 1 year contract |
| NTDGOUT1Y | National Outbound Digital Trunk 1 year |