Nitsuko 85403 ST4 Analog Phone (Black/Refurbished)This Analog Nitsuko ST4 Phone works as an analog set on the system. Other than the first extension in the system, all telephones could be analog phones. Analog telephones connect to ASTU PCBs (pages 14 and 23) or 2 OPX Modules (see Other Station Equipment) below. Key Features: Single line Message waiting lamp Dial mode switch Flash key Last number redial key Volume control This Nitsuko phone works with the 124i 384i system