Reviewed and Updated: September 22, 2026
Use these instructions to change the time and date on Avaya, Comdial, NEC, Nortel, Mitel, Panasonic, Toshiba, Vodavi, and other business phone systems. Select your manufacturer below for model-specific directions.
Older PBX systems may not update automatically when daylight saving time begins or ends. In some installations, the telephone system and voicemail system use separate clocks, so both may need to be updated.
| Manufacturer | Supported systems | Time-change instructions |
|---|---|---|
| Avaya | Partner, Magix, IP Office |
Avaya Partner and Magix Avaya IP Office |
| Comdial / Vertical | DSU, DXP, DX-80, DX-120 | Comdial time-change instructions |
| NEC | Electra, IPK, DSX |
NEC Electra and IPK NEC DSX |
| AT&T / Lucent | Legend | AT&T/Lucent Legend time-change instructions |
| Inter-Tel | Encore, Axxent, GXP | Inter-Tel Encore, Axxent, and GXP time-change instructions |
| Iwatsu | ADIX | Iwatsu ADIX time-change instructions |
| Mitel | SX-50, SX-200, SX-200ML, SX-200 EL, 200 ICP | Mitel time-change instructions |
| Nortel | Norstar, Meridian | Nortel Norstar and Meridian time-change instructions |
| Panasonic | KX series PBX systems | Panasonic KX time-change instructions |
| Samsung | OfficeServ, iDCS |
Samsung OfficeServ time-change instructions Samsung iDCS time-change instructions |
| Siemens | Hicom | Siemens Hicom time-change instructions |
| Toshiba | Strata, CTX | Toshiba Strata and CTX time-change instructions |
| Vodavi | Vodavi business phone systems | Vodavi time-change instructions |
Here are quick easy-to-follow instructions to change the time on older legacy Avaya Partner and Magix PBX systems and the Avaya IP Office.
Avaya Partner &
Magix Systems
Avaya IP Office Time Change Directions
These instructions to change the time are here for Comdial DSU, DXP, and Comdial/Vertical DX-120 and DX-80 PBX Systems.
Comdial Time Change Instructions
Step by step instructions for changing the time on the Lucent (AT&T) Legend Phone systems.
Lucent Legend- changing date and time.
Instructions for changing the time and date on Inter-Tel telephones including the Encore, Axxent and GXP systems.
Change Date & Time on Inter-Tel
Here are the quick instructions for changing the time on Iwatsu Adix Telephones.
Change the time on the Iwatsu Adix
Fast instructions to change the time and date on Mitel SX-50, SX-200 and the SX-200ML & EL and 200 ICP systems.
Change Time on Mitel phone systems
Steps for the Nortel Norstar and Meridian systems to change the time and date.
Changing Time Instruction on Norstar
Change Time on NEC
DSX & DS
Change Time on NEC Electra and IPK
How to change Time on Panasonic KX Series PBXs
Change Time on Samsung OfficeServ Systems
Change Time on Samsung iDCS PhonesStep by Step instructions to change the time for the Siemens Hicom business PBX with an optiPoint telephone picture.
Siemens Hicom Time Change Instructions
Change Time on Toshiba Telephones
When every phone shows the wrong time, the clock is usually controlled by the PBX or main phone system rather than by each individual telephone. Update the time in system programming using instructions for the exact manufacturer and model.
Possibly. Some legacy systems use a separate voicemail server or module with its own clock. After updating the PBX, place a test call and leave a test voicemail to confirm that greetings, message timestamps, and after-hours routing show the correct time.
Many PBX systems use the internal clock for day, night, holiday, and auto-attendant schedules. An incorrect clock can send callers to the wrong greeting, operator, hunt group, or voicemail destination.
Usually no. Follow the exact procedure for the installed system and avoid restarting or initializing a production PBX unless the manufacturer documentation or a qualified telephone-system technician specifically calls for it.