Here's some information on setting up the Meridian 2216 / 2616 phones. These are typically found on an SL-100 switch.
There'll be a button labelled "Program" on the phone, which we will refer to as "P" going forward.
Pressing P and then 6 and 2 (P+62) will bring you to your phone options screen on the phone. If it doesn't, there's something wrong with the phone (bad card inside (which is basically the phone's motherboard), or something else like that). If you use a phone from another station that works, and it still works at the new location, then you know it's the other phone.
These phones (without the add-on module) have 2 rows of 8 buttons. They count UP from the LOWER-RIGHT; 1 is lower-right, 8 is upper-right, 9 is lower-left, and 16 is upper-left.
So, from P+62, in no particular order, the values should be set to:
DTR OFF ..... (P+33)
DCD ON ..... (P+36)
BAUD 9600 ..... (P+22)
PARITY SPACE ..... (P+23)
TERMINAL MODE ..... (P+28)
HOTLINE OFF ..... (P+29)
ASYNC MODE ..... (P+20)
NTKBD DIALING ..... (P+66)
VDN KEY 0 ..... (P+68)
RTS ON ..... (SWITCH ENABLED/DISABLED)
TIMEOUT OFF ..... (SWITCH ENABLED/DISABLED)
VLL OFF ..... (SWITCH ENABLED/DISABLED)
RLB OFF ..... (SWITCH ENABLED/DISABLED)
"SWITCH ENABLED/DISABLED" means that their switch technicians have to set this for us.
We don't care about the following settings:
DM-DM IN USE
So, if you see while doing a P+62 that DTR is set to ON, you'd do a P+33 and use the arrow keys on the phone to set it to OFF.