| Key Symbol and Name | Generic Name | Model Number | Bus | Comment | NCM Required |
|---|---|---|---|---|---|
| A=DIDCSU | Dual Integrated E1 /T1 DSU/CSU | DIDCSU 2912 | ACP | 2 net ports, two data ports, maps DS0s across backplane bus if used with NCM; mini-DACS | Yes, only to map DS0s card to card |
| B=DIU/DBU | DIU with Dial Backup | DIU 2130/DBU | TABS | Modified DIU 2130, Dial backup | No |
| C=CSU | TAC card | TAC 2010 | TABS | T1 CSU, use w/ or w/o DIU card(s), uses backplane if using DIU | No |
| D=DIU | Data Interface Unit | DIU 2130 | TABS | DSU used with TAC 2010 or DIDCSU across Bus | No |
| F=DIU/DDS | DDS Data Interface Unit | DIU 2130 56K NMS | TABS | DIU 2130 modified for DDS remote circuits bundled into a T1 | No |
| G=DHDM | Dual port DS3 | HDM 2182 | ACP | T3 net and two HSSI data ports | For far end functions |
| H=ATM/IMUX | N/A | N/A | N/A | Not available | N/A |
| I=IDCSU | IDCSU; T1 Integrated DSU/CSU | TAC 2130; TAC 2130-S; TAC 2130-T | TABS | T1 CSU/DSU in one card; does not & will not use backplane to other cards | No |
| J=PEP | Protocol Engine Processor | N/A | N/A | Not available | N/A |
| K=DAC | Digital Cross Connect | N/A | N/A | Not available | Yes |
| L=HLM | High/Low Module | DIU 2131 | TABS | DSU w/ one V.35 and one RS 232 | No |
| M=IMUX | Inverse Multiplexer | IMUX 2160 | TABS | IMUX 2160 uses QUAD 2164 | No |
| N=NCM | Node Controller Module | NCM 2000 | BOTH | Management only--no data traffic | N/A |
| P=DPRI | Dual Primary Rate Interface | DPRI 2922 | ACP | ISDN DSU with backup capability; requires NCM | Yes, for ISDN or Backup |
| Q=QUAD | Quad Card | QUAD 2164 | ACP | QUAD 2164 used with IMUX 2160, four E1/T1 CSUs each | No |
| R=SUBRATE | SRDM | DIU 2140 | TABS | Five port RS232 subrate TDM. Used w/ TAC 2010 | No |
| S=HSM | M13 DS3 Multiplexer | M1-3 Mux | ACP | Will be available in AS3000 product line | N/A |
| T=HDM | Single port DS3 | HDM 2180 | ACP | T3 net and one HSSI data port | For far end functions |
| U=DCSU | Dual CSU | DCSU 2911 | ACP | Two T1 or E1 CSUs in one card; CSU only | No |
| V=VCU | Voice Channel Unit | N/A | N/A | Not available | Yes |
| X=QPRI | Quad Primary Rate Interface | QPRI 2921 | ACP | Four port T1 CSU, the first two ports may be used for ISDN lines | Yes, for ISDN |